The work at Chieveley will include a new three-kilometre stretch of the A34 under the M4 - meaning through traffic will no longer need to use the roundabout.

The scheme is expected to take around 18 months to complete and will cost almost �40m.

The interchange of the M4 and the A34 was recently named as the eighth most congested in the country.

As part of the improvements there will also be seven new bridges and new access arrangements to the service station, maintenance depot and hotel.

An exhibition of the changes is being put on show at Chieveley Village Hall on Friday and Saturday.