Nick Clegg is celebrating after what he described as a "stunning" by-election victory in Eastleigh, where his former Cabinet colleague Chris Huhne resigned in disgrace.
But there was a setback for his coalition partner David Cameron with the Tories forced into third place by UKIP.
Political correspondent Carl Dinnen reports:
The Conservative Party has a habit of turning a drama into a crisis. Especially when the background to the drama is Europe.
The wider political impact of parliamentary by-elections often turns out to be more important than the result – Eastleigh is no exception.