The government's plans to allow homosexual and lesbian couples to form legally binding civil partnerships have run into trouble in the House of Lords.

Ministers in the Lords refused to take part in any further debate on the Civil Partnership Bill after peers voted to extend it to other couples, including carers and sisters who lived together.

The vote essentially scuppered the central element of the legislation - which was framed solely for same-sex partnerships.

Ministers say unmarried heterosexual couples already have some partnership rights and believe the option of a registry office marriage effectively affords them the same rights.

The move, which was led by Tory peers, deals a blow to Michael Howard's bid to rebrand the Tories as a gay-friendly party.

The legislation is now in limbo until the government decides its next move.

The issue of civil partnership rights was being seen as a key indicator of Howard's ability to challenge the "nasty party" image.

In the Commons Tory MPs were given a free vote although Howard let it be known that he believed the party should support the measure.