London Road was closed near to the Beaumond Cross junction at 9am Wednesday morning due to emergency repair work.
Cadent - formerly National Grid Gas Distribution - is carrying out emergency work to repair a gas leak.
Cadent have advised "To keep road-users and our staff safe there is a partial road closure, which came into effect this morning. It is not known exactly how long the repair will take but we are working to complete this as soon as possible.
We are sorry for any inconvenience caused to people but for everyone's safety it is vital that we carry out this repair."