A city bus route, described as the hardest service to fulfil in Oxford, is to be split in two to try to make it more reliable.

Traffic jams and roadworks are being blamed for the unreliability of the 10/10A city circle bus, which links the city centre with the John Radcliffe Hospital, Headington, Wood Farm and Cowley.

The problem, coupled with driver shortages, has led to Stagecoach's decision to split the city circle into two separate sections from Sunday.

The 10 will follow its current route, but will terminate in Templars Square, Cowley. The 10A will start from Oxford rail station, go to Cowley Road, then through Hollow Way to the Churchill Hospital and on to the John Radcliffe Hospital.

Services will increase from every 20 minutes between the John Radcliffe Hospital and Cowley, to running every 15 minutes.

But the changes mean residents of Wood Farm and Horspath Road face catching two Buses to the city centre.

In Masons Road, Wood Farm, there will only be a bus every 30 minutes to Headington. Stagecoach says the changes benefit the majority.

Stagecoach's marketing manager David Whitley said customer feedback suggested people would prefer a reliable bus every half-hour than an unreliable service every 20 minutes.

He said: "You would be lucky if the buses are on time at the moment. Buses are more likely to be on time with these changes.

"The city circle is the hardest service to provide in Oxford because it passes through almost every congestion blackspot in the city. Cutting the circle in two will improve reliability."

The service was due to be axed in the evenings and on Sundays, but Oxfordshire County Council has now negotiated a deal with Chiltern Queens bus company, based in Woodcote, near Reading, to save this part of the service.

For now, Chiltern Queens' 10C and 10D service will follow the original city circle route, while the situation is assessed. But it will be cut to an hourly service.

County public transport manager Dick Helling said: "We felt that the complete withdrawal in the evenings and Sundays should not be done in a hurry."

Surveys will be carried out before councillors consider whether the subsidy should continue after February 2002.

Stagecoach says it could resume the full service when staffing problems are resolved.