New laws going through Parliament could in theory give checkout staff powers to fine shoplifters.

The prospect was revealed in the Lords by Lib Dem peer Lord Dholakia during a debate on the Police and Justice Bill.

Part of the Bill provides ministers with delegated authority to specify unlimited categories of people who police chiefs can then accredit with powers to give fixed penalty notices.

Lord Dholakia explained that under Clause 15 of the legislation there would be no restriction on the groups of people who could be specified. "The government could use this power to give punitive powers to wholly inappropriate groups of people," added the peer.

As well as checkout staff, possible candidates for the new powers include school dinner ladies with powers to fine pupils for fighting in the playground or bouncers being allowed to fine pub-goers for being drunk.