Leased Line vs Fibre Broadband: Which Is Better for UK SMEs?

For businesses today, there is no excuse to not have fast, convenient and reliable internet. Whether your business is running cloud applications, hosting video meetings, or supporting remote workers, the right connectivity can make or break productivity. Two of the most common options for UK businesses are leased lines and fibre broadband.

But which one is right for your organisation?

In this SME broadband comparison, join us as we’ll explore the differences in speed, reliability, contention ratios, and cost, helping you make an informed decision.

What Is Fibre Broadband?

Fibre broadband is a high-speed internet service delivered via fibre optic cables. In the UK, this usually means either:

• FTTC (Fibre to the cabinet) – fibre cables run to your local street cabinet, with the final connection via copper.
• FTTP (Fibre to the premises) – full fibre all the way to your building.

For SMEs, fibre broadband is often the most accessible and cost-effective choice, with speeds up to 1Gbps now common across much of the UK. However, you need to remember that it’s a contended service, meaning you share bandwidth with other users in your area.

What Is a Leased Line?

A leased line is a dedicated internet connection provided directly to your business premises, and unlike fibre broadband, it’s uncontended, meaning your business doesn’t share bandwidth with anyone else.

Leased lines are symmetrical, offering the same upload and download speed, making it ideal for businesses using VoIP, video conferencing, or large file transfers. Fun bonus – they also come with strict Service Level Agreements (SLAs) guaranteeing uptime, support, and repair times.

Leased Line vs Fibre Broadband: Main Comparisons

Here’s a breakdown of the main differences UK SMEs should consider before makinga final decision:

Reliability and Uptime

For many SMEs, downtime is costly, and a leased line comes with enterprise-grade SLAs, often guaranteeing a fix within 4–6 hours. Fibre broadband, on the other hand, typically comes with best-effort support, which can mean waiting 24–48 hours for a fix.

If your business relies on constant connectivity (for customer service platforms, financial transactions, or cloud apps) leased lines are the safer choice.

Speed and Symmetry

Fibre broadband is usually asymmetrical, with much faster download than upload speeds. That’s fine for general browsing, but SMEs that upload large files, run VoIP systems, or host video calls may find uploads limiting.

Leased lines deliver symmetrical speeds, ensuring uploads and downloads are equally fast, making collaboration and cloud-based work far smoother.

Contention Ratios Explained

One of the biggest differences between leased lines and fibre broadband is contention ratio. Fibre broadband is shared with multiple users, so speeds can fluctuate during peak hours.

Leased lines are 1:1 uncontended connections so your business gets 100% of the bandwidth, 100% of the time. For SMEs that cannot afford bottlenecks, this is a decisive factor.

Cost Comparison

For SMEs, we think the cost gap between leased lines and fibre broadband is narrowing. While leased lines remain the premium option, competition among UK providers is driving prices down.

• Fibre broadband: £30–£100 per month (depending on speed and location).
• Leased line: £200–£800+ per month (depending on bandwidth and provider).

Although leased lines are more expensive, the investment pays off for SMEs that need guaranteed performance and uptime.

UK Providers Offering Leased Lines & Fibre Broadband

Which Is Best for Your SME?

• We suggest you choose fibre broadband if your SME needs affordable connectivity for general use, with occasional video calls, cloud apps, and browsing.
• and choose a leased line if your business relies on 24/7 uptime, heavy data usage, cloud-first infrastructure, or you simply cannot risk downtime.

For SMEs scaling fast or operating across multiple sites, leased lines provide the future-proofed reliability needed to grow.

Our Final Thoughts

In the debate of leased line vs fibre broadband for UK SMEs in 2025, the decision largely comes down to cost vs reliability. Fibre broadband is affordable and fast enough for many smaller businesses, but leased lines remain the gold standard for mission-critical operations.

Before deciding, weigh up your SME’s reliance on cloud, remote working, and customer-facing applications. If downtime or poor upload speeds could cost your business money, a leased line may be the smarter investment.