Three days in three months - that's how much time a businessman says he has lost sitting in Oxford's traffic jams.

The Green Road roundabout roadworks in Headington have been blamed for citywide delays as people abandon usual routes into the city - resulting in a network of blocked roads.

Keith Slater, a former Chamber of Commerce president, has lost a day a month stuck in traffic since the work began and believes a congestion charge is the only answer.

He said: "We need to charge people early in the morning who come into Oxford to park for the day. That's the time we want to be discouraging people.

"I use park and ride all the time. There would have to be a very special reason for me to use my own car."

Mr Slater, a managing director of Burford-based Caprese bedding and furniture shop, said Oxford's traffic problems could damage the city's economy.

He said: "High Wycombe is developing and is going to be as big as Oxford - people will start going there to shop instead.

"We need to be prepared to take radical action. Everyone was up in arms about London's congestion charge but now it's accepted."

But Oxfordshire County Council is not in favour of it. David Robertson, the council's cabinet member for transport, said: "It's not our policy and we are not considering it in any form."

John Goddard, the leader of Oxford City Council, said: "Congestion charging has got to be kept on the agenda of things to think about in the future - but there are lots of small things to do first.

"For example, making the best possible use of public transport - to make it as affordable and as accessible as possible."

People who use the roads on a daily basis say traffic in the city is getting worse.

Oxford Brookes University facilities manager Mike Newell, who works with Stagecoach to run Brookes buses, said: "We've had 40 to 50-minute delays because the approach to the A40 is often down to one lane causing tail-backs all the way to Wheatley.

"Car drivers are using other routes which is having a knock-on effect to both our major routes - the U1 and U5 - making students and staff late."

Oxford Bus Company director Louisa Weeks said: "We are constantly monitoring our running times and have recently put extra recovery time into our schedules to help us maintain a reliable service."

Royal Cars taxi company manager Ibrar Mohammed said: "We have experienced a lot of problems. It's affecting our drivers' livelihoods.

"We don't know whether to take on jobs because we can't tell how long it will take to get to customers."

Linda Simon, who works for market research company AC Nielsen in Headington, said: "People are coming in late because of the roundabout - you don't know when to expect delays."

Work on the Green Road roundabout - to turn it into a 'hamburger' junction - is due to be finished in December.