Too many drivers are being jailed for motoring offences, the head of the Prison Service has warned.

Martin Narey said yesterday the prison system was in danger of being overrun by motoring offenders and other petty criminals as the courts imposed increasing numbers of jail sentences.

The result had been a fourfold increase in the number of convicted drivers behind bars over the past decade, he said.

Many offenders were now languishing in jail who should have been dealt with by way community penalties.

"The Prison Service is being overrun with very many short-term prisoners - lots of people who are in prison now who would not have been in prison ten years ago," he told BBC1's Breakfast with Frost.

"Custody rates for some quite petty offending have quadrupled, motoring offences for example. Custody rates at the magistrates' courts for men and women convicted of motoring (offences) are four times higher now than they were ten years ago. They don't need to be in jail in such numbers."

His comments were seized on by campaigners, who claimed that motorists were being jailed because they were seen as an easy target.

"Prison is intended as a method by which we remove dangerous people from society - murderers, rapists, people who damage others," said a spokesman for the Association of British Drivers.

"It is an improper use of the tool to send people to jail for a minor motoring offence."

He said prosecutions for serious motoring offences had dropped over the past decade, while the number of speeding offences had soared.

"When you have a situation like this, respect for the law starts to break down. The law itself needs to be re-examined."

The AA was more guarded, saying that most motorists who were sent to prison had committed serious offences such as driving while disqualified, driving without insurance and causing death by dangerous driving.

Andrew Howard, the AA's head of road safety, said there was growing public support for jailing such offenders.

"What else can you do with someone who has ignored a court order or has killed someone on the road?" he said.

Mr Narey, who is set to become head of the merged prison and probation services, said he wanted to work with the courts to reduce the numbers of drivers sent to jail.

"The new service which I will head will work very closely with the judiciary to try to inform them about the greater effectiveness of community penalties," he said.