David Cameron is under pressure to return to core Conservative values as the party's dismal showing in the Eastleigh by-election triggered a new bout of soul-searching in the Tory ranks.
The Prime Minister has insisted there would be no change of direction, despite seeing his party slump to third place behind the UK Independence Party in a seat they had hopes of winning.
But he is facing a growing groundswell of discontent among Tory backbenchers who fear the rise of Ukip could put paid to their chances of winning an outright majority at the next general election.
Tory Party vice chairman Michael Fabricant - who was heavily involved in the Eastleigh campaign - has warned the Conservative high command that the result cannot be dismissed as a mid-term protest vote.
He said the party had struggled to present a distinctive message while Ukip had managed to connect with traditional blue-collar Tory voters on issues such as immigration and crime in a way that the Conservatives had not.
"The Conservative voice is muffled and not crisp. It does not clearly project Conservative core policies or principles," he wrote on his Twitter page. "With Ukip clearly announcing policies the public want to hear, we must do the same. 26 months to go (to the next general election) boys and girls..."
Tory backbencher Colonel Bob Stewart said there was widespread dismay among the rank-and-file about the direction the party was taking, and he warned the leadership could not afford to ignore their concerns. "This is a wake-up call to the Conservative Party," he said. "If the Conservative Party at the top doesn't get the message, we will soon bring it home because backbenchers like myself are extremely concerned about what has happened."
The demands for a more distinctive Conservative agenda will once again heighten tensions within the coalition.
In contrast, the Liberal Democrats have been feeling a sense of relief after successfully fending off the Ukip challenge in Eastleigh to hang on to the seat previously held by disgraced former Cabinet minister Chris Huhne.
The party also had to endure days of damaging headlines relating to the alleged conduct of its former chief executive Lord Rennard in the final run-up to polling day. The peer has strongly denied the claims of inappropriate behaviour towards women Lib Dem activists.