Mobile phone thieves could face up to five years in jail or an unlimited fine under tougher sentences introduced at the beginning of the month.

Coupled with the fact eight in 10 phones are blocked within 48 hours, the message from the Government, police and mobile phone industry is, these devices are not worth stealing anymore.

The tougher sentences will be meted out when a new offence is introduced tomorrow; that of offering to or agreeing to (or offering or agreeing for a third party to) re-programme a mobile phone.

Introducing tougher penalties for this crime forms part of Labour's drive to tackle the problem of street crime. By making mobile phones less attractive to criminals, it is hoped this will help drive down street crime and make people safer in their communities.

It is also greatly helped by the fact the mobile phone industry is able to block these phones within hours of being reported stolen. Independent test results show that the Mobile Industry Crime Action Forum collaboration between the Government, mobile phone industry and the police - has made good its pledge to block access for stolen mobiles across all networks.

The tests reveal that 80 per cent of mobile phones reported stolen are blocked within 48 hours. Jack Wraith, of the Mobile Phone Industry Crime Forum (MICAF), said this was a "significant step" in helping reduce handset theft in the UK.

Home Secretary John Reid said: "Being robbed for your mobile is a harrowing and distressing experience that has happened to far too many of us and our children. We are determined to stamp this out.

"That's why today we're dealing mobile thieves a double whammy. If they try to use the stolen mobile they now know it will be blocked within 48 hours.

"And a new offence from tomorrow means that if they try and re-programme it - or try and sell it for re-programming - they can face up to five years in prison or an unlimited fine.

"This shows what can be done when Government, police and industry work in partnership. Because crimes – like mobiles themselves - are always changing we will now work with the industry and police to anticipate the crimes of the future so we can design out problems in the next generation of phones before they develop."

However, the police urged the public not to be complacent.

Tim Godwin, Association of Chief Police Officers lead on mobile phone crime and Assistant Commissioner at the Metropolitan Police, said: "The National Mobile Phone Crime Unit continues to work closely with UK forces and industry… [but] we would advise people to use their phones safely and wisely and be aware of the environment they are in.

"I would also urge everyone to register their mobile phone and any other identifiable property on the immobilise website. This service is free and will assist in the recovery of your property should it be lost or stolen and will also help catch the people engaged in stealing phones."