Leased Lines vs FTTP: Which Is Best for Your Business?

For UK businesses that depend on reliable internet connectivity — which, in 2026, is essentially all of them — the choice between a leased line and Fibre to the Premises (FTTP) broadband is one of the most important infrastructure decisions you will make. Get it right, and your team enjoys seamless cloud access, crystal-clear video calls, and zero excuses for downtime. Get it wrong, and you are left battling contention, asymmetric speeds, and SLAs that are not worth the paper they are written on.

The trouble is, the marketing from internet service providers often blurs the lines between these two fundamentally different products. Both promise “fibre” connectivity, both quote impressive headline speeds, and both claim to be ideal for business use. But beneath the surface, they are engineered for very different purposes, carry very different guarantees, and come with very different price tags.

In this comprehensive guide, we break down every meaningful difference between leased lines and FTTP for UK businesses — from speed and reliability to cost, SLAs, contention ratios, installation timelines, and real-world use cases. By the end, you will know exactly which option is right for your organisation.

What Is a Leased Line?

A leased line is a dedicated, private data connection between your business premises and the provider’s network. Unlike broadband — which shares infrastructure with other users — a leased line gives you an exclusive, uncontended circuit that is yours alone. No other business or residential customer shares your bandwidth, ever.

Think of it as the difference between a private road and a motorway. Both get you from A to B, but the private road is never congested, never speed-limited by other traffic, and comes with a guaranteed maintenance contract. The motorway is cheaper, generally faster in off-peak hours, but grinds to a crawl during rush hour — and there is nothing you can do about it.

Leased lines deliver symmetric speeds, meaning your upload speed matches your download speed. This is critical for businesses that rely on cloud backups, video conferencing, VoIP, uploading large files, or hosting on-premises services. With standard broadband — including many FTTP packages — upload speeds are a fraction of download speeds, creating a bottleneck that many businesses do not notice until it causes real problems.

Key Characteristics of a Leased Line

• Dedicated, uncontended bandwidth — the full speed is available 24/7, regardless of what anyone else is doing
• Symmetric upload and download speeds — typically from 10Mbps up to 10Gbps
• Backed by enterprise-grade SLAs — with guaranteed uptime, fix times, and financial compensation for breaches
• Static IP addresses included — essential for VPNs, remote access, hosting, and certain compliance requirements
• Priority fault repair — typically 4–6 hour fix times for critical faults
• Longer installation lead times — usually 30–90 working days due to dedicated infrastructure provisioning

What Is FTTP Broadband?

FTTP stands for Fibre to the Premises — a broadband connection where the fibre-optic cable runs all the way from the exchange to your building. This is distinct from FTTC (Fibre to the Cabinet), where fibre reaches a roadside cabinet and the final connection to your premises uses old copper telephone lines, severely limiting speed and reliability.

FTTP represents a massive leap forward from FTTC and traditional ADSL. It can deliver download speeds of up to 1Gbps (or even higher with some providers), and the connection is inherently more stable than anything involving copper. For many small businesses, FTTP provides more than enough bandwidth at a fraction of the cost of a leased line.

However, FTTP is still a contended, shared service. Your connection shares capacity with other users on the same network segment. During peak usage times — typically weekday mornings and early afternoons in business areas — your actual throughput may drop below the headline speed. The degree to which this affects you depends on your provider’s contention ratios and network management practices.

Key Characteristics of FTTP

• Shared infrastructure — bandwidth is contended with other users on the same segment
• Asymmetric speeds — download speeds far exceed upload speeds (e.g. 900Mbps down / 110Mbps up)
• Best-effort SLAs — most business FTTP packages offer limited or no uptime guarantees
• Faster installation — typically 2–4 weeks where infrastructure already exists
• Significantly lower cost — often £30–£80 per month for business-grade packages
• Dynamic or shared IP addresses — static IPs may be available as an add-on

Speed Comparison: Leased Line vs FTTP

On paper, FTTP headline speeds can match or even exceed those of a leased line. A 900Mbps FTTP connection from BT or Openreach looks comparable to a 1Gbps leased line. But headline speed tells only half the story. The real-world performance difference comes down to three factors: consistency, symmetry, and contention.

Metric	Leased Line	FTTP Broadband
Download speed (typical)	100Mbps – 10Gbps	36Mbps – 1.8Gbps
Upload speed (typical)	100Mbps – 10Gbps (symmetric)	10Mbps – 220Mbps
Speed consistency	Guaranteed minimum (usually 100%)	Best-effort; varies with demand
Latency	1–5ms (very low)	5–20ms (low to moderate)
Jitter	Sub-1ms	1–10ms
Packet loss	Near zero	Occasional during congestion

The upload speed difference is where leased lines truly shine. A business running cloud-hosted CRM, regular video conferencing for 20+ users, or large daily backups will quickly feel the constraint of FTTP’s asymmetric upload. Uploading a 10GB backup over a 115Mbps FTTP connection takes approximately 12 minutes; on a symmetric 500Mbps leased line, the same upload takes under 3 minutes.

The chart above makes the asymmetry unmistakable. While FTTP delivers impressive download figures, the upload speeds — critical for cloud-first businesses — lag dramatically behind a leased line’s symmetric capability.

SLA Differences: Guarantees That Matter

An SLA (Service Level Agreement) is where the rubber meets the road. It defines what your provider guarantees in writing — and, crucially, what financial compensation you receive when they fail to deliver. This is one of the starkest differences between leased lines and FTTP, and one that many businesses underestimate until they experience their first extended outage.

Leased Line SLAs

Enterprise leased lines come with robust, contractually binding SLAs that typically include:

• Uptime guarantee: 99.95% – 99.99% (equivalent to a maximum of 4.4 hours – 52 minutes of downtime per year)
• Target fix time: 4–6 hours for critical faults, often with escalation to 2 hours for premium SLAs
• Proactive monitoring: the provider monitors your circuit 24/7 and often detects faults before you do
• Service credits: financial compensation (typically a percentage of monthly rental) for each hour of SLA breach
• Guaranteed throughput: 100% of the contracted speed, 100% of the time

FTTP SLAs

Business FTTP packages offer significantly weaker guarantees:

• Uptime target: typically “best efforts” with no formal guarantee, or a loose 99.0%–99.5% target
• Target fix time: often “next business day” or “within 48 hours” — sometimes longer
• No proactive monitoring: you report faults; they respond
• Limited service credits: many providers cap compensation at a pro-rata refund for the days of outage
• No throughput guarantee: speeds are advertised as “up to” and can vary

Understanding Contention Ratios

The contention ratio is the number of users who share the same bandwidth capacity on a given network segment. It is one of the most important — and least understood — factors in business broadband performance.

A leased line has a contention ratio of 1:1. The circuit is yours and yours alone. If you are paying for 500Mbps, you get 500Mbps at 3 PM on a Tuesday just as reliably as you do at 3 AM on a Sunday.

FTTP broadband typically has contention ratios ranging from 20:1 to 50:1 for residential packages, and 10:1 to 20:1 for business-grade packages. This means that up to 20 other customers may share the same upstream capacity. In practice, not everyone uses their connection simultaneously at full speed, so the impact varies — but during peak business hours, the degradation can be noticeable and unpredictable.

These progress bars illustrate the approximate percentage of headline bandwidth you can realistically expect during peak business hours. A leased line delivers 100% of its rated speed at all times; FTTP performance degrades as contention increases.

Cost Comparison: What UK Businesses Actually Pay

Cost is where the conversation gets uncomfortable for leased line advocates, because there is no getting around it — leased lines are significantly more expensive than FTTP broadband. The question is whether the premium is justified by the performance, reliability, and guarantees you receive in return.

Product	Speed	Monthly Cost (typical)	Installation Cost	Contract Length
Business FTTP	150Mbps / 30Mbps	£35–£55	£0–£50	12–24 months
Business FTTP	500Mbps / 73Mbps	£45–£70	£0–£100	12–24 months
Business FTTP	900Mbps / 115Mbps	£55–£85	£0–£100	12–24 months
Leased Line	100Mbps symmetric	£200–£300	£0–£2,000	12–36 months
Leased Line	500Mbps symmetric	£300–£500	£0–£3,000	12–36 months
Leased Line	1Gbps symmetric	£400–£650	£0–£5,000	12–36 months

Installation costs for leased lines vary enormously depending on your location and the distance to the nearest point of presence (PoP). In central London and major business parks, installation may be included in the contract. In more rural or suburban locations, excess construction charges (ECCs) can run into thousands of pounds. Some providers waive or spread these costs over longer contract terms.

FTTP installation is generally free or nominal where Openreach infrastructure is already in place, making it the obvious choice for businesses that need to get connected quickly without a large upfront investment.

Installation Timelines: Planning Ahead

One of the most overlooked differences between leased lines and FTTP is the time it takes to get connected. If you need internet access quickly — for a new office, a relocation, or an emergency replacement — this factor alone may determine your choice.

Connection Type	Typical Lead Time	What Affects It
FTTP (infrastructure exists)	2–4 weeks	Standard Openreach provisioning and router delivery
FTTP (new build required)	4–8 weeks	Duct work, cabling, and wayleave permissions
Leased Line (PoP nearby)	30–45 working days	Site survey, circuit provisioning, carrier lead times
Leased Line (ECC required)	45–90 working days	Excess construction, wayleaves, council permissions

This is why many businesses that ultimately want a leased line will install FTTP or a business broadband connection first as a temporary measure, then migrate to the leased line once it is provisioned. At Cloudswitched, we regularly manage this transition for clients — ensuring continuity throughout the switch.

Leased Line vs FTTP: Head-to-Head Comparison

Here is the definitive side-by-side comparison to help you decide which connection type aligns with your business requirements.

Use Cases by Business Size

There is no one-size-fits-all answer. The right choice depends on your headcount, how you use technology, your budget, and your tolerance for risk. Here is how the decision typically breaks down across different business sizes in the UK.

Micro-Businesses (1–5 Employees)

For very small businesses — a sole trader, a small consultancy, or a startup working from a single office — FTTP is almost always the right choice. The cost of a leased line is disproportionate to the number of users, and the reliability of modern FTTP is more than sufficient for light to moderate cloud usage, email, and occasional video calls.

Recommended: Business FTTP (150–500Mbps) at £35–£70/month. Consider a 4G/5G backup dongle for resilience.

Small Businesses (6–25 Employees)

This is where the decision becomes more nuanced. If your team relies heavily on cloud-hosted applications, VoIP, and video conferencing, you will start to notice the limitations of FTTP — particularly the upload bottleneck and the lack of guaranteed performance during peak hours. However, if your usage is relatively light and downtime of a day or two per year is acceptable, FTTP remains viable.

Recommended: Business FTTP (500–900Mbps) for light usage; a 100–200Mbps leased line for cloud-dependent operations. Consider FTTP as a primary with a leased line failover, or vice versa.

Medium Businesses (26–100 Employees)

At this scale, a leased line is strongly recommended as the primary connection. With 26+ staff all accessing cloud applications, running video calls, and transferring files simultaneously, contention on FTTP will cause noticeable degradation. The business case for a leased line is also easier to justify — the per-user cost of a £400/month leased line across 50 staff is just £8 per person per month.

Recommended: 200Mbps–1Gbps leased line as primary, with FTTP as a backup/failover connection.

Larger SMEs & Multi-Site Businesses (100+ Employees)

Businesses of this size almost universally require a leased line — and often multiple connections for redundancy, WAN links between sites, or dedicated circuits for specific applications. FTTP may still serve as a cost-effective failover or for guest Wi-Fi, but the primary connectivity must be enterprise-grade.

Recommended: 500Mbps–10Gbps leased line(s) with automatic failover, MPLS or SD-WAN for multi-site connectivity, and FTTP as a secondary backup.

UK Providers: Who Offers What

The UK leased line and FTTP market is served by a mix of national carriers and specialist business ISPs. Here is an overview of the major players and what they bring to the table.

Provider	Leased Lines	Business FTTP	Notable Strengths
BT Business	10Mbps – 10Gbps	36Mbps – 900Mbps	Largest UK network; widest coverage; strong SLAs
Virgin Media O2 Business	100Mbps – 10Gbps	100Mbps – 1Gbps	Own fibre network; competitive pricing in urban areas
TalkTalk Business	10Mbps – 1Gbps	36Mbps – 900Mbps	Budget-friendly; good for cost-sensitive SMEs
Vodafone Business	10Mbps – 10Gbps	36Mbps – 900Mbps	Strong mobile bundle options; convergence plays
CityFibre	100Mbps – 10Gbps	Via partners	Major alt-net; rapidly expanding full-fibre footprint
Colt Technology	100Mbps – 100Gbps	N/A	Enterprise-focused; excellent SLAs; strong in London
Neos Networks	100Mbps – 100Gbps	N/A	Extensive UK backbone; competitive wholesale pricing
Zen Internet	100Mbps – 1Gbps	36Mbps – 900Mbps	Award-winning customer service; transparent pricing

One important consideration: you do not have to go directly to a carrier. Working with a managed IT provider like Cloudswitched gives you access to multiple carriers through a single relationship. We compare pricing across all available networks at your postcode, negotiate the best rates, manage the installation, and provide ongoing support — so you get the right connection at the right price without having to navigate the carrier landscape yourself.

The Hybrid Approach: Why Many Businesses Choose Both

An increasingly popular strategy among UK SMEs is to deploy both a leased line and FTTP at the same premises. This hybrid approach delivers the best of both worlds:

• Primary connection: a leased line carrying business-critical traffic — VoIP, cloud applications, VPN, and customer-facing services
• Secondary connection: FTTP handling less sensitive traffic — general web browsing, guest Wi-Fi, software updates, and serving as an automatic failover if the leased line goes down

With proper SD-WAN or load-balancing configuration, traffic can be intelligently routed across both connections to maximise performance and ensure resilience. If the leased line fails, all traffic automatically switches to FTTP within seconds. If FTTP degrades during peak hours, critical traffic remains on the leased line unaffected.

The combined cost of a 200Mbps leased line (£250/month) and a 500Mbps FTTP connection (£50/month) is approximately £300/month — less than a single 500Mbps leased line, but with greater resilience and more total bandwidth available. For many businesses, this represents the optimal balance of performance, reliability, and value.

Making the Right Decision for Your Business

To summarise the decision framework:

Choose FTTP if:

• You have fewer than 10 employees with moderate internet usage
• Your budget is under £100/month for connectivity
• You can tolerate occasional speed fluctuations and longer fault resolution times
• You do not rely heavily on upload-intensive applications
• You need to get connected quickly (within 2–4 weeks)

Choose a leased line if:

• You have 10+ employees who depend on cloud applications and VoIP
• Downtime directly costs you revenue or damages client relationships
• You need guaranteed symmetric speeds for uploads, backups, and video
• You require contractual SLAs with financial penalties for breaches
• You operate in a regulated industry where connectivity resilience is a compliance requirement

Choose both if:

• Maximum resilience is essential — you cannot afford to be offline for any reason
• You want to separate business-critical and general traffic
• You are willing to invest in SD-WAN or intelligent failover to optimise both connections

Whichever route you choose, the key is making an informed decision based on your actual business requirements rather than headline marketing claims. The cheapest option is rarely the most cost-effective when you factor in the real cost of downtime, lost productivity, and frustrated staff.