What Is a Leased Line? A Plain-English Guide for UK Businesses

What Is a Leased Line?

A leased line — also called an Ethernet leased line, dedicated internet access (DIA), or private circuit — is a dedicated internet connection provided exclusively to a single business. It forms part of the broader connectivity landscape available to UK organisations, representing the premium tier of business internet access. Unlike standard broadband, which is a shared service where many businesses and homes use the same physical exchange infrastructure simultaneously, a leased line is yours alone. The bandwidth is not shared, contended, or affected by what other businesses in your area are doing.

Leased lines are point-to-point connections: a dedicated fibre circuit runs from your premises directly to the carrier's point of presence, and from there to the internet. This dedicated path is what makes leased lines fundamentally different — and in many cases fundamentally better — than broadband for business use. With the UK average broadband speed reaching 69.4 Mbps in 2024 (Ofcom, UK Home Broadband Performance Report 2024), broadband speeds have improved significantly, but the shared nature of that infrastructure means those speeds are not guaranteed — a critical distinction for businesses that depend on consistent connectivity.

Leased Line vs Broadband: Key Differences

The differences between a leased line and a business broadband connection go beyond speed. The core distinctions that matter for business use are:

• Uncontended bandwidth: The speed you pay for is the speed you get, at all times. No slowdown during peak hours. No sharing with neighbours or other businesses on the same exchange.
• Symmetric speeds: Upload and download speeds are equal. A 100 Mbps leased line delivers 100 Mbps in both directions. Broadband is asymmetric — typically much slower on upload, which creates bottlenecks for VoIP, video conferencing, and cloud backup.
• Static IP address: A leased line comes with a block of static public IP addresses allocated exclusively to your business, essential for VPN, firewall whitelisting, and cloud access policies.
• SLA with compensation: Leased lines include a service level agreement guaranteeing uptime (typically 99.99% or higher) with financial compensation if the target is missed. Broadband SLAs are typically best-efforts with no compensation.
• Dedicated support: Leased line faults are treated as priority issues with faster response and resolution targets than residential or standard business broadband faults.

These differences are not merely technical specifications — they translate directly into operational reliability. A business running hosted telephony, cloud-based ERP, or supporting remote workers via VPN experiences the impact of these differences every day.

Types of Leased Line

Several types of leased line are available in the UK, each with different characteristics and price points:

• Ethernet Access Direct (EAD): The most common type, providing a dedicated fibre circuit from your premises to the carrier's exchange. Available from 10 Mbps to 10 Gbps. This is what most businesses mean when they refer to a leased line.
• Ethernet over FTTC (EoFTTC): A lower-cost alternative that uses the existing FTTC infrastructure but with a dedicated, uncontended service. Speeds are limited compared with full EAD but pricing is significantly lower. Suitable for businesses that need better reliability than broadband but cannot justify full leased line cost.
• Dark fibre: An unlit fibre pair between your premises and the carrier's exchange, with you providing the active electronics. Used by larger organisations with specific technical requirements or very high bandwidth needs. The UK business broadband market is worth approximately £4.2 billion (Ofcom, Communications Market Report), and dark fibre represents the premium end of this market.

Leased Line Speed Options

UK leased lines are available from 10 Mbps up to 10 Gbps, with the most common speeds for SMEs being 100 Mbps, 500 Mbps, and 1 Gbps. The right speed depends on the number of users, the nature of the workloads, and the type of services running over the connection.

As a rough guide: a 100 Mbps leased line comfortably supports 30 to 50 office workers using cloud applications and VoIP; a 500 Mbps line suits 100 to 200 users or businesses with heavy cloud data transfer requirements; a 1 Gbps line supports larger organisations or those running hosted infrastructure, cloud-based ERP systems, or large file transfers as routine business operations.

Because leased lines are symmetric, upload speed matters as much as download. Businesses backing up to cloud storage, using hosted phone systems, or running video conferencing at scale benefit particularly from the symmetric bandwidth that broadband cannot provide. With 96% of UK premises now having access to superfast broadband of 30 Mbps or above (Ofcom, Connected Nations 2024), even fast broadband connections are limited by their asymmetric nature — upload speeds on FTTC broadband are typically only 10 to 20 Mbps regardless of the download speed.

Leased Line Costs in the UK

Leased line costs vary significantly based on location, speed, and provider. The primary cost driver is the distance from your premises to the nearest carrier exchange or point of presence. As a guide for current UK pricing:

• 100 Mbps: Approximately £200 to £400 per month in urban areas; up to £500 in semi-rural areas
• 500 Mbps: Approximately £300 to £600 per month
• 1 Gbps: Approximately £437 to £994 per month depending on provider and location

Prices are typically quoted on 36-month terms. Shorter terms are available but at higher monthly cost. Installation costs vary — urban locations with existing carrier infrastructure nearby can have zero or low installation charges, while rural or hard-to-reach sites may incur significant excess construction charges (ECCs). AMVIA provides transparent pricing and compares quotes from multiple carriers to find the most competitive option for your specific location.

Lead Times and Installation Process

Leased line installation typically takes 30 to 90 days from order to go-live. The process involves several stages: a site survey to assess the fibre route from the nearest exchange to your premises, wayleave agreements if the fibre route crosses third-party land, civil engineering works to lay the fibre, and finally the installation of the network termination equipment inside your building.

The main variable in lead time is how much civil engineering work is required. In established business parks and city centre locations where carriers already have infrastructure nearby, installations are typically at the shorter end of the range. In rural or remote locations, new fibre may need to be laid over longer distances, extending the timeline. AMVIA advises starting the leased line procurement process at least 60 days before the required go-live date.

SLA and Uptime Guarantee

A leased line SLA typically guarantees 99.99% or higher availability, equivalent to less than nine hours of unplanned downtime per year. Unlike broadband, where SLAs are largely symbolic, leased line SLAs include financial compensation — typically a refund of monthly rental charges for periods of downtime that breach the guaranteed targets.

More importantly, leased line SLAs specify response and fix times: a typical business leased line includes a four-hour response target and a next-business-day fix target, with enhanced SLAs available offering four-hour fix guarantees for businesses where downtime carries significant financial consequences. AMVIA manages fault reporting and SLA compliance tracking on behalf of managed connectivity clients.

Who Needs a Leased Line?

A leased line is appropriate for any business where reliable, high-performance internet connectivity is critical to operations. Practical indicators include: 20 or more staff sharing a single internet connection; heavy use of cloud applications including Microsoft 365, hosted phone systems, or cloud-based ERP; on-site servers or hosted infrastructure that staff access remotely over VPN; video conferencing as a daily business requirement; or any compliance or contractual requirement for guaranteed bandwidth and SLA.

For businesses that do not yet require a full leased line, FTTP coverage has expanded significantly — reaching 62% of UK premises by January 2025 (Ofcom, Connected Nations Update 2025) — providing a high-speed alternative at lower cost. AMVIA advises honestly on whether a leased line or business broadband is the right choice for your specific requirements and budget.