Drivers in Oxford will face a night-time diversion on the city ring road.

A no-right-turn restriction, which could last for three weeks, began last night at the Heyford Hill roundabout.

Work at the congested junction, to create a ‘hamburger’ roundabout like the one at Green Road, Headington, began in April and is expected to finish next month.

The supermarket giant Sainsbury’s is expanding the store next to the roundabout in a multi-million-pound revamp and it will be officially relaunched next month. Sainsbury’s spokesman Sam Hinton said: “The no-right-turn restriction could last three weeks, but it anticipated it will only last 10 days.”

Charles Turner, of ABC Taxis in Oxford, said: “We will certainly be alerting our drivers to this.”

The roundabout is being rebuilt by contractors acting for Sainsbury’s.

The restriction, between 7.30pm and 6.30am, is being introduced so that resurfacing work can be completed.

Drivers affected will be those travelling northwards from the A4074 on to the A4142, and those heading south-eastwards from the A423 on to the A4074.

These drivers will be directed to the next junction where they can turn around and then reapproach the Heyford Hill roundabout from the Kennington (Abingdon Road) roundabout to the south, or from the Rose Hill (Littlemore) roundabout to the north.

Drivers face 30mph limits on all routes leading to the roundabout. When work began in April bus companies said their vehicles were experiencing delays of 10 to 15 minutes at the roundabout.