The students of the worst performing driving instructors in the county are four times less likely to pass their test than their more successful rivals.

While the lowest ranking instructors only achieve 20% pass rate for their pupils their high-flying colleagues see four in five of customers pass.

But instructors warned the figures could be misleading as some instructors manipulate pass rates to appear more successful.

Figures from the Driving and Vehicle Standards Agency (DVSA), which do not reveal instructors names, reveal the poorest performing instructor at the Crawley test centre achieved just a 21.6% pass rate with 87 fails between January 1, 2011 and December 31, 2013. The best performing instructor had an 82.7% pass rate with just 23 fails over the same period.

The picture is the same across the county with instructors using the Burgess Hill centre boasting pass rates ranging between 27.6% and 81.8% while at Worthing test centre instructors pass percentage ranged between one in four tests passed and four in five.

Nick Haskoll, of nmh driving, which covers Brighton and Hove and the surrounding areas, said: “Some instructors may put people in for their test when they are not necessarily ready for a number of reasons, possibly because that learner keeps nagging to be put in for their test.

“When they present for test the driving instructor may not present their Approved Driving Instructor number, they may take it out of their car for the test and that test then isn’t recorded against that instructor.

“There isn’t anything illegal about this but it means that pass rates aren’t necessarily an accurate representation of what is going on.”

A DVSA spokeswoman said: “The pass rate of a driving instructor is not necessarily a reflection of their teaching standard.

“Instructors may not have trained the candidate but only presented them for the test; some instructors also focus on training candidates who have difficulty in learning to drive.