The closure of Oxford and Banbury's motorcyclist test centres could spark an increase in illegal riders and casualties on the road, claim an instructor and learner riders.

From September 29, motorcyclists' licence tests will no longer be held in Hollow Way, Cowley, or West Bar Street, Banbury, with learners having to take tests in Newbury or Swindon.

The move coincides with the launch of a new motorcycle test, which includes off-road exercises.

New "supercentres", where car and motorcycle tests can be taken, are replacing existing sites - but the Driving Standards Agency has been unable to find a suitable location in Oxfordshire.

It means learner riders will have to travel at least 20 miles on busy roads to reach test centres, which is causing concern among instructors. It has also prompted a surge in riders wanting to take their test before September.

John Wheeler, who has been training learners for more than 40 years, said it was causing "hysteria" and could have serious con- sequences.

The 64-year-old, from Kidlington, said: "There will be no test centre within a reasonable travelling distance of Oxford. Riders are panicking and are wanting to rush in to take their test before the new date."

Figures from the DSA show almost 1,000 people took motorcycle tests in 2006-7 in Oxfordshire - 439 in Oxford and 543 in Banbury.

DSA spokesman Chris Lee said: "The centres are being developed to provide a safe environment in which to carry out the new and more demanding motorcycle exercises required by European Union legislation. They are being introduced in response to alarming motorcycle casualty statistics.

"We have been looking high and low to try to find a site for one of the new centres in Oxford, but to no avail, so we have had to extend our search."

The routes riders will have to take to reach test centres have also caused concern. There were three fatal accidents involving motorcycles on the A420 between Oxford and Swindon from January 2005 until December last year, along with two serious collisions and one collision causing minor injuries.

On the A34 from Oxford's Pear Tree Interchange to Newbury there were three serious motorbike collisions and eight slight injury collisions over the same period.

Learner riders currently have to wait about six weeks for a test date in Oxford, but Mr Wheeler fears this could become much longer.

He said: "After September, I hate to think what it will be like. People will be more inclined to ride illegally if they're unable to obtain a test within a reasonable time and travelling distance."

Chris Hart, a 17-year-old A-Level student from Witney, began lessons last month. He said: "I want to take my test as soon as possible. Once the Oxford test centre closes, it will be a lot harder to get to the new centre, wherever it may be, and it will be tougher to afford it all."

Leon Ravenhall, 23, from Bicester, has been taking lessons for three weeks. He said: "I realise better testing will save lives, but only if it's accessible to learners.

"Having to travel all the way to Swindon or Newbury, and taking your test on roads you don't know, will cause problems."