Sex offenders tracking plan shelved

Ministry of Justice (MoJ) officials said the project had been shelved until there had been "developments in technology".

A two-year pilot scheme was launched in 2004 as part of the Government's so-called "prisons without bars" project, but studies found the equipment had serious drawbacks.

For example, the signal could be blocked or distorted by high rise buildings or even trees.

An assessment published by the MoJ last July found one in four sex offenders freed early on a satellite tag were reconvicted of a further offence within a matter of months.

The technology involved offenders wearing an ankle bracelet similar to conventional electronic tags, which relayed their movements via satellite to a control room.

Entering an "exclusion zone" - such as a paedophile going near a children's playground or school - would trigger an alarm.

Ministers are now believed to be pinning their hopes on using lie detectors as a new technique to deal with paedophiles.

Assistant general secretary of probation union Napo, Harry Fletcher, said: "The abandonment of satellite tracking comes as no surprise. It was hugely expensive and the signal failed when confronted with tall buildings, low cloud or other obstacles."

H added: "It remains the case, however, that sufficient controls should be in place for each individual case to maximise public protection."