A £4M project to improve one of Oxfordshire’s worst traffic trouble-spots begins tomorrow, but the roadworks will last until Christmas.

Motorists are being warned to allow extra time to travel through the M40-A34 interchange at Wendlebury, near Bicester.

Narrow lanes, 40mph speed restrictions and temporary overnight lane closures will be in force on and around the roundabout for the next five months.

Villagers in the area have welcomed the changes, but fear rat-running on minor roads will increase during the work as drivers try to avoid the junction.

Phase one of the planned improvements to the interchange at junction nine of the M40 will see the southbound motorway exit slip road widened and entry to the A34 improved, to try to end tailbacks which can stretch from the roundabout back on to the motorway.

But a planned £6.5m second phase, to smooth the flow of traffic on to the northbound M40 and to and from the A41, has been put on hold, pending the Government’s spending review in the autumn.

Once its budget is settled by ministers, Highways Agency officials will decide whether they can provide funding for the extra work.

Julian Cordy, the chairman of Wendlebury Parish Council, said: “The junction is a problem when there’s heavy traffic, because people use the village as a rat-run. The work they’re planning should help that.”

However, he added: “There will be ‘roadworks ahead’ signs on the A41 and A34 during the project and we fear people will see these and then think ‘I’ll nip through Wendlebury’.

“We have asked for ‘no access through the village’ signs, but we have had no response.”

The Highways Agency said there would inevitably be disruption during the work, but said it would do all it could to minimise problems.

The project will get under way tomorrow with lane closures between 10pm and 5am every night until Sunday. The northbound M40 exit slip road will be closed, with diversions in place.

Highways Agency spokes-man James Wright said that when completed, the work would increase capacity and improve vehicle flow.

A lane will be added to the southbound exit from the M40 and an extra lane will be provided at the start of the southbound carriageway of the A34.

The second phase alterations would create extra lanes on the northbound exit of the A34 and increased capacity on the A41 heading towards Bicester.

Mr Wright said: “We have plans for it and it’s part of the improvements we want to make.”

He added that work would, if possible, be suspended over the August Bank Holiday.

For more information about the project, see the Highways Agency website.