The Conservative's deputy Treasurer has quit in protest over David Cameron's supposed "lurch to the right".
Businessman Johan Eliasch, a major Conservative donor has resigned from his honorary position as deputy Treasure of the party.
Friends of Mr Eliasch told the Times the Anglo-Swedish business tycoon believed it was a "mistake" to move the party to the right and Mr Cameron should stick to the consensual form of politics which saw the party's popularity surge in his first few months as leader.
The Conservatives, however, claim Mr Eliasch - a long-standing environmental campaigner - has resigned to concentrate on his other projects, such as the Cool Earth initiative with Labour MP Frank Field.
A party spokesman said: "Johann Eliasch has stood down as a deputy treasurer to focus on climate change issues, however, his full and financial support for David Cameron's leadership continues."
Mr Eliasch's resignation reinforces the impression the Conservatives are "lurching to the right" as Mr Cameron seeks to narrow Labour's lead under Gordon Brown.
Since returning from holiday, Mr Cameron has spoken strongly on crime, immigration and social breakdown, leading to accusations the Conservatives are returning to their core vote.
Labour's response to Mr Cameron's campaign against "anarchy in the UK" has remained relatively muted, with some suggesting the government would welcome Mr Cameron's retreat to "traditional" Conservative priorities.
But recent opinion polls show the strong lead enjoyed by Mr Brown is June and July is beginning to falter. Since Mr Cameron's return to the UK, some polls claim he is neck-and-neck with the prime minister.