Nigel Farage's party is fielding a record 1,734 candidates, just 22 fewer than the Lib Dems.
The PM's decision to reject calls for a "viable cheaper option" represents an opportunity for Labour to woo the Lib Dems.
With hung parliaments likely to become the norm, the kind of strop that Tory MPs are now throwing will be utterly counterproductive.
The policy is cited by party activists as one of the main reasons voters turned against the party in 2010 after "Cleggmania".
The Lib Dems have a simple choice – either they back their flagship policy by voting for Labour's motion or they don’t.
Former Lib Dem energy secretary and his former wife jailed.
Every wing, arm and leg of the party is livid about this. Clegg can't shrug the defeat off.
An unlikely political alliance is formed as both men argue that health spending should not be protected while other services are cut.
If Clegg supports the motion, he will enrage the Tories. If he opposes it, he will be accused of another "betrayal".