More than a fifth of those who voted Liberal Democrat at the general election are now supporting Labour, according to a poll.
Research by ComRes for the Independent provided more evidence of the impact from the decision to sign up for coalition government.
Just 62% of those who backed Nick Clegg's party on May 6 said they would do so again now.
The proportion saying they had switched allegiance to Labour rose from 15% to 22% since last month, while 7% said they would back the Conservatives.
But the Lib Dems appear to have arrested the slump in their overall poll standing after receiving 22% of votes at the election.
The Lib Dems were up two points on 18% this month, while the Tories were down one on 38% and Labour up one on 34%.