"As far as I'm aware, there is no new plan," says Liberal Democrat president Tim Farron.
The Prime Minister is "entitled to pitch to his own backbenchers that they should change their mind and keep to the agreement" on Lords reform, he told ITV News.
Mr Cameron told his MPs there would be a 'small' elected element under new House of Lords proposals.
"If he wants to describe that as small, he's a good spin doctor," Mr Farron said.
ITV News learns that Mr Cameron hadn't squared his watered-down Lords plan with Nick Clegg and the Lib Dems.
In his final Prime Minister's Questions before recess, the man in question looked as though he needed a holiday more than ever
The Government has retreated on its plans to reform the House of Lords after dropping a vote on the timetable for legislation.