Full Breakdown
Bat Tunnel Installed Beneath New A421 Dual Carriageway to Safeguard Wildlife
9/8/2026, 12:52:58 AM
Core Development: Wildlife Underpass Completed
National Highways has finished a 45-metre (148 ft) long, 4.5-metre-high (15 ft) “bat tunnel” beneath the newly built 10-mile (16 km) stretch of the A421 dual carriageway. The underpass runs between the Black Cat roundabout in Chawston, on the outskirts of Bedford, and the Caxton Gibbet roundabout near Cambridge. Designed to guide bats and other local mammals across the road, the structure is integrated into the embankment and is accompanied by new hedgerows, trees, shrubs, and specially engineered fencing that direct wildlife toward the crossing.
Project Context and Scale
The A421 upgrade, part of a £1 billion road programme, aims to ease congestion and shorten journeys between Milton Keynes and Cambridge. Approximately 80,000 drivers use the Black Cat roundabout each weekday, prompting the need for a faster, higher-capacity route. The wildlife tunnel was not budgeted separately; it was incorporated into the overall scheme as the standard design used for major road projects. The road is slated to open in the spring following completion of the tunnel.
Data and Statistics
Official Statements & Responses
National Highways explained that ecological surveys identified bat flight paths and informed the placement of the underpass. The agency emphasized that the tunnel provides a “safe route for all wildlife,” allowing animals to move between habitats split by the new carriageway. It also noted that the accompanying vegetation and fencing are intended to encourage use of the crossing by bats and other mammals.
Why It Matters
By embedding a dedicated wildlife corridor within a major transport upgrade, the project seeks to balance infrastructure development with biodiversity protection. The underpass aims to reduce road-kill incidents and maintain ecological connectivity while delivering faster travel for tens of thousands of motorists each day.
