The M40 links London with Oxford, Banbury, Warwick and Birmingham. This page gathers what National Highways is reporting on the motorway right now — incidents, roadworks, lane closures and overnight closures — so you can check the road before you join it.

The newest reports are listed first. If nothing appears, there is nothing reported that we are aware of at the time the list was last refreshed.

The M40 at a glance

The M40 runs for 89 miles, from Junction 1 at Denham on the edge of London to Junction 3A of the M42 south of Birmingham. It passes through Buckinghamshire, Oxfordshire, Northamptonshire and Warwickshire, linking London, Oxford and Birmingham.

It was built in stages. The first section, between Handy Cross at High Wycombe and Stokenchurch (Junctions 4 to 5), opened in June 1967. The road reached Great Milton, at Junction 8, in 1974. The extension to Birmingham came much later: the section between the M42 and Warwick opened in December 1989, and the remaining 48 miles opened in January 1991.

Driving the M40

Leaving London, the M40 is at its busiest between the M25 and High Wycombe. Beyond Junction 5 it passes through the Stokenchurch Gap, a chalk cutting up to 47 metres deep in the Chiltern Hills, and enters Oxfordshire. It passes east of Oxford, turns north at Junction 8, and runs through open country past Bicester and Banbury before reaching Warwick and Leamington Spa. Active Traffic Management is used on the approach to the M42 at the northern end of the M40.

How busy is the M40?

The Department for Transport measures traffic at 33 count points on the M40. In the 2025 figures the busiest stretch is between the M25 at Junction 1A and Beaconsfield at Junction 2, carrying 136,403 vehicles a day. The average across all 33 count points is 85,733 vehicles a day.

The London end is clearly the heaviest. The two stretches either side of Beaconsfield both carry more than 130,000 vehicles a day, while most of the road north of Oxford sits between about 88,000 and 100,000. The short stretch between Warwick and Leamington, Junctions 14 to 15, stands out again at 113,433. See how busy the M40 is, junction by junction.

Where the M40 meets other roads

• Junction 1A — the M25, for Heathrow, Watford and the M1. Our sister site M25 Traffic covers the orbital.
• Junction 4 — the A404 for Marlow, Maidenhead and the M4. See M4 Traffic.
• Junction 8 — the A40 for Oxford and Cheltenham.
• Junction 9 — the A34 for Oxford and Newbury, and the A41 for Bicester and Aylesbury.
• Junction 10 — the A43 for Northampton and Milton Keynes.
• Junction 15 — the A46 for Coventry and Stratford-upon-Avon.
• M42 Junction 3A — the end of the M40, for Birmingham, Solihull, the NEC and the airport. See M42 Traffic.

Find what you need

• Latest M40 traffic news — every report, newest first.
• M40 roadworks and closures tonight.
• M40 accidents and incidents.
• Northbound and southbound traffic.
• Junction maps and service areas.

The M40 has four service areas: Beaconsfield, Oxford, Cherwell Valley and Warwick.

Traffic count figures on this page are from the Department for Transport road traffic statistics, 2025.