Measures to crack down on cowboy wheelclampers have taken effect.

Clamping on private land without a licence becomes a criminal offence in England and Wales with offenders facing fines of up to £5,000 and up to five years in prison.

Clamping on private land was ruled to be "extortion and theft" in Scotland and has been banned since 1992.

Now anyone wishing to clamp on private land in England and Wales will have to obtain a £190 licence issued by the Security Industry Authority (SIA) and will also have to attend a 30-hour course.

The SIA will be able to refuse licences to those with criminal records. An SIA spokesman said: "We hope this will weed out the cowboys, although it will still be the responsibility of motorists to ensure they do not park where they shouldn't"

She added that the SIA had sent out 1,500 licence application forms and had received around 600 applications which were being processed and had granted 200 licences.

Typically, licences will be issued to people who want to clamp in such places as hospital grounds and private car parks.

Under the conditions of the licence, clampers will not be able to clamp, block or tow away emergency vehicles or vehicles in which a valid disabled badge is displayed.

One group welcoming the new regulations is the RAC Foundation which has long campaigned to "limit the excesses of private clamping companies".

The foundation listed the following cases:

Clampers demanding a lady's gold tooth or sexual favours in lieu of payment

Clampers clamping a hearse with a body in the back

Clampers in Doncaster threatening to hold a mother's three-year-old daughter hostage until she collected £60 from a bank

The foundation's executive director Edmund King said: "The licensing of clampers is a victory for motorists. Cowboy clampers have been allowed to get away with their unscrupulous activities for far too long."