Does Your Business Need a Leased Line?

The AMVIA Team | 7 min read · Mar 2026

A business leased line is a dedicated, uncontended circuit — and the decision to buy one should be driven by evidence about your traffic, not sales pressure. Below, we set out exactly when the premium is justified and when high-speed business broadband remains the smarter spend.

What is the core difference between broadband and a leased line?

Broadband is contended and asymmetric; a leased line is uncontended, dedicated, and symmetrical with a hard SLA. On broadband you share capacity with other premises on the same exchange or cabinet, so peak-time speed varies. A leased line gives you the same speed every hour of every day.

Standard business broadband — whether FTTC or FTTP — is a contended product. Your connection shares capacity with neighbouring businesses and households, and Ofcom's own guidance explains that advertised speeds are a "best efforts" maximum rather than a guarantee (Ofcom). In most circumstances that works, because not everyone maxes out their bandwidth at once. During sustained peaks, the shared model becomes a constraint.

A leased line is an uncontended, dedicated circuit. Nobody else shares your bandwidth. Your 100Mbps is 100Mbps at 9am on Monday, lunchtime on Wednesday, and 5pm on Friday. It is symmetrical — upload equals download — and ships with a formal SLA defining exactly what the provider does, and how fast, when a fault occurs. For the full primer, see what is a leased line.

What are the seven signs your business needs a leased line?

The clearest signals are peak-time slowdowns, poor VoIP quality, remote-working bottlenecks, long cloud-backup windows, public-facing servers, more than 30 concurrent users, and costly downtime. If several of these apply at once, dedicated internet access is usually the right call.

1. Slow performance at peak times. If broadband performs well at quiet times but slows during business hours, the issue is contention. A speed test at 8pm will look very different from one at 10am on a weekday. If the morning test regularly shows speeds well below the advertised figure, your connection is contended beyond its practical capacity.

2. VoIP call quality issues. Call quality is sensitive to latency, jitter, and packet loss — all worsened by congestion. Choppy audio, delayed responses, or dropped calls during busy periods usually trace back to the connection. A leased line's consistent low latency fixes this structurally rather than relying on QoS tuning over a contended line. If voice is business-critical, pair connectivity with VoIP security.

3. Remote-working performance problems. Teams hitting a central VPN, hosted desktop, or on-premises apps need consistent upload at the office end. Broadband upload is often asymmetric — a 300Mbps FTTP product may give only 50Mbps upload. For a heavily remote organisation, that low office-end upload bottlenecks everyone working remotely.

4. Cloud backup and data replication windows. Nightly backups of multi-gigabyte or multi-terabyte datasets need enough upload to finish inside the window. A connection with 20Mbps upload takes over 6 hours to push 50GB; a 100Mbps leased line completes the same upload in roughly 66 minutes. As data volumes grow, upload becomes the binding constraint.

5. Hosted services or public-facing servers. Any business running public web servers, customer-facing apps, or hosted services needs a static IP, consistent upload, and a formal SLA. Broadband static IPs exist but carry no upload guarantee. A leased line provides all three as standard — the appropriate infrastructure for anything externally accessible.

6. More than 30 users on one connection. Thirty simultaneous users on video conferencing, Microsoft 365, and cloud apps generate peak combined demand around 60–120Mbps in a typical 2026 cloud-first office. FTTP at 300Mbps has download headroom, but if upload demand is similarly high, the asymmetric profile starts to constrain performance. Above 30 cloud-intensive users, a leased line is usually the right answer.

7. Downtime has serious financial consequences. Broadband has best-efforts fault response and rarely commits to resolution within hours. If transactions, operations, or customer service effectively stop during an outage, the case is simple: the cost of an extended outage almost certainly exceeds the monthly premium of a dedicated circuit. Resilience planning is core to operational risk management, as the NCSC sets out in its guidance for organisations (NCSC).

When is broadband still the right answer?

For businesses under 20 users, with no hosted services, no heavy upload needs, and reasonable tolerance for the occasional slow period, FTTP broadband offers excellent value and sufficient performance. The gap has narrowed as full-fibre has expanded, and many firms that once needed a leased line now meet their needs on gigabit FTTP at a fraction of the cost.

The right answer depends on your usage pattern, team size, and tolerance for performance variation. AMVIA assesses client connectivity requirements before recommending a product, rather than defaulting to the higher-margin option. One provider. Security-first. Microsoft-certified.

How much more does a leased line cost than broadband?

Expect a clear premium for the dedicated bandwidth, SLA, and symmetrical speeds — but the gap has tightened with full-fibre. A 100Mbps leased line in a well-connected location typically costs more than equivalent FTTP, and whether that premium is justified depends entirely on the financial impact of the reliability and upload difference.

A 100Mbps leased line in a well-connected location typically costs from £69/month, compared to from £35/month for high-speed FTTP broadband. A 1Gbps leased line is available from £129/month depending on provider and location. (Source: AMVIA pricing data.)

If resilience is the driver rather than raw speed, a cheaper path is often a leased line as primary with broadband backup connectivity for automatic failover — and a leased line security layer to protect the circuit.