A new law will make it an offence to reprogram a mobile phone, it is reported.

A Home Office spokeswoman has confirmed the government will unveil "a new measure" against mobile phone crime on Friday.

A bill on mobile phone reprogramming is due to be published in the House of Lords, she said.

The Times newspaper reports that the emergency legislation will make it an offence to reprogram a mobile phone by putting a new identity number on a stolen handset.

It says the Mobile Phone (Reprogramming) Bill could lead to jail sentences of up to five years for anyone caught doing so.

Specialist software

Mobile phone operators have already agreed to exchange lists of the unique 15-digit handset identity numbers, known as the International Mobile Equipment Identity (IMEI) numbers, which are programmed on manufacture.

Thus, when a phone is reported stolen, its number can be recognised by other networks and they can refuse to connect it.

However, this system alone does not make stolen handsets impossible to use.

Some thieves with specialist software can still change the handset identity number, or alter it to disguise its origin.

This makes it impossible for the manufacturers to trace the handsets, and they can then be sold on.

Welcomed

While some mobiles are sent abroad for reprogramming, gangs also carry out the operation in Britain, and resell the handsets for between �10 and �60, the Times reports.

The government move to tackle this trade is likely to be welcomed by the industry.

Phone security experts have for some time been calling for the changing of the IMEI number to be made illegal.

Jack Wraith, executive secretary of the Mobile Industry Crime Action Forum, told The Times: "We see this as another piece of the crime prevention jigsaw and fully support this type of initiative."

Official figures showed that 700,000 handsets were stolen in England and Wales last year, many in violent attacks.