Michael Howard veered sharply to the right under Crosby and only increased is hare of the vote by 0.7%.

Cameron speechwriter: Don’t let Crosby drag Tories to the right

Cameron speechwriter: Don’t let Crosby drag Tories to the right

David Cameron is in danger of making the same mistakes as his predecessors and taking the Tories to the right, his former speechwriter said today.

Writing in the Independent, Ian Birrell said the prime minister's decision to hire Lynton Crosby to run his general election campaign suggested he was giving up on attracting voters from outside his core supporters.

"It is a step back into the nasty party past, a major setback for the modernisers trying to turn the Tories into a more powerful and positive electoral force in tune with a changing nation," he wrote.

"If the Tories revert to his reactionary tricks, they risk profound damage to their long-term prospects."

Crosby became famous in Australia for helping Conservative John Howard to four election victories, but his detractors claim he whipped up suspicion of immigrants using 'dog whistle' politics – right-wing messages designed to win the support of racists without overstepping the mark of acceptable debate.

"Crosby's appointment raises fears the Conservatives are set to repeat the mistake they made under their three last leaders," Birrell said.

"They set out to appeal to the centre ground then, under pressure from vociferous voices on the right, tacking sharply towards the core vote."

The concern around Crosby is emphasised by the failure of Mitt Romney in the US. The Republican candidate lost predominantly because he failed to reach out beyond his party's base supporters to ethnic minorities, women and young people.

Cameron faces a similar problem, with right-wing backbenchers demanding the party shift to the right on issues such as tax and law and order.

Crosby was behind both of Boris Johnson's victories in the London mayoral elections, allowing many Tory backbenchers to champion him for the 2015 fight, but some commentators suggest the mayor was actually hampered by the Australian's rigid order.

The election strategist instantly caused controversy over the weekend when it was alleged he used the phrase "f***ing Muslims" while working for Johnson.

"These are very serious allegations, which call into question the prime minister's decision to appoint Lynton Crosby," Labour's vice-chair Michael Dugher said.

"These allegations must be investigated and if they are true, David Cameron must condemn them."