Highways officials have made last-minute changes to a controversial road scheme in Witney after admitting it could cause “undesirable” congestion.

Last night campaigners against the Cogges Link Road accused Oxfordshire County Council of making the change “on the hoof”.

The council has decided to alter the road’s junction with Cogges Hill Road from a T-junction to a roundabout.

Documents showing the changes were presented on day nine of the public inquiry into the road.

The changes were made following evidence on traffic flows by Iain MacNeil, who was called by The Mawle Trust, which owns land needed for the road and is against the scheme.

Mr MacNeil’s traffic modelling showed during peak afternoon traffic in 2028, some drivers travelling from Oxford Hill would struggle to turn right into the Cogges estate due to the amount of traffic moving in the opposite direction.

His modelling showed they would have to travel the full length of the link road, turn around at the Station Lane roundabout and travel back to turn left into the estate on Cogges Hill Road.

If motorists chose to wait for an opening to turn right, the model predicted queues and delays for drivers travelling along the link road from Oxford Hill.

The county council described this as “undesirable”.

Wyn Devonald, member of anti-link road group Witney First, said: “One has to ask why the council is still modifying the plans – they have had years to get it right.

“It is shambolic and the whole planning exercise is being made on the hoof.”

Mawle Trust trustee James Mawle said: “We identified the problem, the council has now accepted it and has altered the scheme to accommodate it. They are trying to make the scheme acceptable but they cannot get away from the basic fact the scheme is a monstrosity. It is lipstick on a pig.”

At the inquiry yesterday, inspector Stephen Roscoe said: “It is right that the council respond to certain objections as they see fit.

“From what I have seen, it is in certain respects a response to matters raised during the inquiry.”

Mr Roscoe said there were benefits of presenting the alteration now, saying: “It does mean I have the opportunity to hear from objectors on these particular points.”

County council spokesman Marcus Mabberley said: “We have listened to representations from objectors regarding this area and have subsequently altered the plan to have a roundabout there instead of a T-junction.”

The inquiry was due to finish yesterday but will now run until at least Tuesday.

It will decide whether the county council can compulsory purchase land needed for the scheme.

The Cogges Link Road aims to cut congestion and pollution in Witney town centre and will run from Oxford Hill to Station Lane.