Key West London Route to Close for Essential Safety Upgrades

A major route in west London will be closed for more than a month to allow important safety improvements to take place, Transport for London (TfL) has announced.

The A40 will be shut in both directions between the Westway roundabout and the Marylebone flyover starting at 22:00 on Friday 20 March, with the closure expected to remain in place until late April.

The A40 Westway is one of the busiest roads managed by TfL, carrying around 96,000 vehicles every day, making it a vital route connecting west London with the city centre.

TfL’s Chief Capital Officer, Stuart Harvey, said the works were necessary to maintain the long-term safety and reliability of the structure.

He explained that it is essential the flyover remains properly maintained to ensure it can continue to support the tens of thousands of road users who rely on it daily. The planned improvements will help ensure the structure continues to operate safely for years to come.

The elevated carriageway is supported by approximately 20 reinforced concrete bridge structures, originally constructed between 1969 and 1970. As part of this stage of the project, engineers will replace two expansion joints on the Marylebone flyover. These joints are critical components that allow the bridge structure to safely expand and contract in response to temperature changes and traffic movement.

According to TfL, the engineering work involved is particularly complex, meaning the entire carriageway must be closed for the duration of the project.

The closure has been scheduled to begin during the Easter period, when traffic volumes are generally lower. TfL says it has also attempted to coordinate the works to minimise overlap with other major road projects across the capital.

Despite this planning, motorists have been warned that diversion routes and surrounding roads are likely to experience significant congestion throughout the closure.

Drivers travelling between the M25 and central London via the A40 are being advised to use the M4 and A4 as alternative routes.

Those moving between outer London and the city centre are encouraged to use the A312 Parkway or the A406 North Circular Road to connect with the M4 and A4 corridors.

Local residents are also being encouraged to consider public transport options, including Tube, rail and bus services, or where possible to walk or cycle. However, TfL has noted that some bus services may also experience disruption as a result of the closure.

Once this phase of the work is completed in late April, further disruption will continue. The A40 will then be closed to westbound traffic at the Westway roundabout on weekends, excluding bank holiday weekends, until 6 July, as additional maintenance activity takes place.