The Government last night conceded that rules to minimise excessive food packaging had not fully worked as a Scottish MP launched a parliamentary bid to cut down on supermarket waste.

Within minutes of Jo Swinson, the Liberal Democrat MP for East Dunbartonshire, launching her Packaging (Reduction) Bill, Joan Ruddock, the minister responsible for recycling and waste, acknowledged that voluntary agreements brokered by the government - the so-called Courtauld commitments - were a good start but she was now "pushing the supermarkets to go further". Some 90% of the UK grocery sector is signed up to stop packaging growth by 2008 and to a reduction by 2010.

Earlier, Ms Swinson launched her bid for an ambitious new law to create binding targets and a national organisation to enforce them.

Her bill would also boost powers for trading standards officers, allow consumers to leave packaging in supermarkets or send it back to manufacturers for disposal and introduce a carrier bag deposit scheme.

She explained how five million tonnes of packaging waste was sent to landfill sites every year, and families spent about £470 a year on packaging.