Speculation has continued over the future of Conservative Party chairman Theresa May.

Senior frontbencher Tim Yeo warned Central Office is "blocking" leader Iain Duncan Smith's attempts to reshape the party.

"The party needs to let Iain Duncan Smith lead in the way that previous leaders have. At the moment there are too many elements in the organisation which act as blocks against what he's trying to do," Yeo told The Telegraph.

His comments came after Lord Bell, the former PR guru to Margaret Thatcher, condemned May's decision to brand the Tories as the "nasty party".

Media reports claim Duncan Smith is unhappy with May's performance at central office.

Her relations with the party's director of strategic communications, Paul Beaverstock, are said to be strained.

Differences between May and Duncan Smith were heightened earlier this year following the decision to sack party chief Mark MacGregor.

May sided with the party's executive board which was heavily critical of the decision.

Yeo, tipped as a likely successor as party chairman, argued that the Tories should focus resources with a "laser-like intensity" on target seats.

"Our focus has to be on the seats where the result of the next election will be decided," he said.

Yeo also warned that the run of bad news for the government would not necessarily deliver a massive boost to Conservative election fortunes.

"We mustn't assume that just because things have gone badly for Labour the country is about to turn to the Conservatives," he said.

"We can't assume that a slump in Labour's support automatically leads to a Conservative government."

Political rivals of the Conservatives seized on the signs of discord inthe senior ranks.

Liberal Democrat parliamentary party chairman Mark Oaten claimed rows in the Conservative were now part of the summer season.

"May may stay, or May may go, but the simple fact is that the Tories are unwilling and incapable of being led as a party whoever becomes leader and whoever chairs the party," he said.

"The reality of the polls is that the Conservatives are still not seeing any real sign of a breakthrough despite Labour's problems.

"The latest Populus poll shows a mere nine point difference between all three parties with the Liberal Democrats on 25 per cent. And in the last big test of public opinion - the May local elections - the Liberal Democrats scored 30 per cent of the votes."