An alliance of bishops, senior Liberal Democrats and independent peers will attempt to derail a key element of the Government's welfare reforms today by voting against plans for a £26,000-a-year cap on benefits.
In a move that will embarrass Nick Clegg, the former Liberal Democrat leader Lord Ashdown said yesterday he would rebel against the Government for the first time over the measure because of the "unacceptable" hardship it would cause children.
He is expected to be joined by other Liberal Democrats, including Lord Oakeshott, the party's former Work and Pensions spokesman in the Lords, leading bishops and large numbers of cross-benchers, to oppose the extent of the benefits cap in a vote on the proposals in the House of Lords tonight.
"I [have] voted with the Government on everything until now," Lord Ashdown said. "I see it as my job as an ex-leader to support my successor but I will not support the benefit cap in its present form."
Lord Oakeshott said a cap was acceptable "in principle", but he added: "Many of us back the bishops' argument that, as it stands, the Bill could split families and visit the sins of the fathers on the children."
Under proposals put forward by the Work and Pensions Secretary Iain Duncan Smith, the total amount of benefit that working-age people could receive would be capped so that households on out-of-work benefits did not receive more than the average weekly wage earned by working households.
In a rare move by a member of the Lords Spiritual, the Right Reverend John Packer, Bishop of Ripon and Leeds, has tabled an amendment to the Bill which would exclude child benefit from the cap. He said he had discussed the move with his fellow bishops and it had "extensive" support.