London’s A40 closes for a month from today – here’s the impact it will have

Published March 20, 2026 7:00am

Updated March 20, 2026 9:12am

At 10pm tonight, one of the main roads into central London will close for an entire month.

Drivers are being warned of gridlock around large parts of the city as a result of major engineering works on the A40.

The route is being closed between the Westway roundabout and Marylebone flyover to allow for the works to go ahead.

Nearly 100,000 vehicles a day normally use the route, meaning that roads surrounding the flyover are likely to become clogged up.

One driver who lives in Maida Vale said: ‘This is going to be an absolute nightmare. I have family who live in south west London and getting to them on public transport will be a nightmare. We are trapped.’

Another motorist in Teddington who uses the A4 to get to Kensington said: ‘It’s going to be carnage. The roads around my office are busy at the best of times and with all the other roadworks going on, this is just going to make it worse.

TfL has said that it is carrying out the work over Easter when the roads are less busy.

However, the AA has warned of a ripple effect across all of London and businesses have warned it will have a significant impact on them.

An AA spokesperson said: ‘Traffic will not simply disappear – it will divert onto surrounding routes, increasing congestion across northwest London and putting additional pressure on already busy roads.

‘Drivers should expect delays to “ripple” across the wider network, particularly at peak times, with diversion routes and local roads likely to become heavily congested.’

A40 closure

The primary impact zones are likely to be:

Marylebone and Paddington: This is ‘landing point’ of the flyover. Marylebone Road, Edgeware Road and streets around Paddington Station may witness gridlock
White City and Shepherd’s Bush: Westway Roundabout will be a major bottleneck. Long delays expected around Westfield and the Shepherd’s Bush interchange
Hammersmith and Chiswick: The A4 corridor will likely see a significant increase in traffic as the primary alternative for traffic entering London from the M25
North Circular (A406): Heavy volumes of traffic expected from drivers heading to the M1 or A4/M4

Other bottlenecks facing severe gridlock could include:

Scrubs Lane and Wood Lane: Impacted by traffic towards the north of the closure

Uxbridge Road A4020 and Goldhawk Road: Local relief roads for the A40

Westbourne Grove and Bayswater Road: Potential cut-throughs to avoid Marylebone

Steve McNamara, general secretary of the Licensed Taxi Drivers Association, blamed roadworks for London being the fifth most congested city in the world.

He said: ‘At this rate we will soon be moving up the list and London could add worlds most congested city to its other credits.’

Restaurant owner Ayman Al Zubaidi from Hijazi Corner, Marylebone, shared his concerns about Eid which is being marked tonight.

He said: ‘Most of our customers drive, some come from east London, but a lot of them from west London and places like Acton. I need to let them know about the closure.’