Prime Minister Gordon Brown has been branded a "feartie" by the Scottish National Party after he ruled out an autumn election.
Mr Brown's decision has ended weeks of speculation
The prime minister told the BBC he wanted a chance to show his "vision for change" and to develop his policies.
Recent UK opinion polls have suggested that Labour's lead over the Conservatives has fallen.
SNP leader Alex Salmond said Gordon Brown was a "big feartie from Fife" who had lost credibility.
Speculation had been mounting that the prime minister would call a November election.
At the Scottish Liberal Democrat one-day conference in Glasgow on Saturday, UK leader Sir Menzies Campbell issued a challenge to the prime minister to make a decision over the poll.
The two dates which had been most widely touted for an election were 1 and 8 November.
But Mr Brown, speaking exclusively to the BBC's Andrew Marr on Saturday in Downing St, said: "I'll not be calling an election. I have a vision for change in Britain and I want to show people how in government we're implementing it."
BBC political editor Nick Robinson suggested that the main reason for not calling a snap election was an unfavourable poll of marginal seats showing a swing to Tories.
Gordon Brown explained his decision to Andrew Marr
Mr Salmond said the prime minister had lost "an enormous amount" of credibility and control of his campaign team.
"Gordon Brown is not so much the Grand Old Duke of York - more the big feartie from Fife!" he said.
The first minister added: "Gordon Brown obviously looked at the polls north and south of the Border and ran away at the first whiff of grapeshot.
"Those whom the gods seeks to destroy they first render ridiculous and this shambles leaves Gordon Brown looking totally ridiculous.
"Labour are a shambles north of the Border and shaky south of the Border."
Scottish Conservative leader Annabel Goldie said: "We were ready for a battle but it looks like the prime minister is bottling it.
"Whenever he does pluck up the courage we'll be waiting and ready."
But Mr Brown told Andrew Marr: "Over the summer months we've had to deal with crises, we've had to deal with foot-and-mouth, with terrorism, with floods, we had financial crises.
"Yes, we could have had an election on competence and I hope people would have understood we have acted competently, but what I want to do is show people the vision we have for the future of this country in housing, health and education."