New research published yesterday by theology think tank Theos indicates voters with a religious faith could determine the outcome of the general election.

The Comres poll of 1,000 adults found that while support for the Conservatives among people with no religious affiliation had shot up from 21 per cent to 34 per cent, support among Christians had grown by only 2 per cent to 40 per cent.

The poll found, however, that 48 per cent of Christians were “absolutely certain” to vote, a figure which rose to 61 per cent amongst Christians who said their faith was very important to their lives.

In comparison, only 32 per cent of Muslims said they were “absolutely certain” to vote, well below the national average of 47 per cent.

Surprisingly, the poll found that 57 per cent of Muslims intended to vote Labour, despite it being the party that took Britain into war with Iraq and introduced anti-terror laws.

Commenting on the research, Director of Theos Paul Woolley said: "The result of the election looks too close to call. We're in hung parliament territory.

"The balance of support among the different faith groups shows that the Conservatives cannot afford to lose the current support they have among Christians.

“Labour is in a position where it could benefit from reaching out especially to Christians.

"The problem for Labour is that the people most likely to support Labour are also the least likely to vote.”

Theos attributed the Conservatives’ meagre gains amongst Christians to negative perceptions about the party’s attitude to the faith. Only 21 per cent of people believed the Conservative Party had been the friendliest to the Christian faith in recent years, only slightly above the 20 per cent for Labour and 9 per cent for the Liberal Democrats.

The party most likely to attract voters with no religious affiliation is the Liberal Democrats, scoring 26 per cent of people with no religion.

"The UK isn't like the United States, but the religious vote is going to be a critical factor in determining who gets into Number 10 – especially when it comes to appealing to female voters," said Mr Woolley.

People who said their faith was very important to their lives were more likely to believe that religious freedom had been restricted in the UK in the last 10 years. While thirty-two per cent of people agreed with the statement, that figure jumped to 51 per cent among Christians who said their faith was very important to their lives, and to 53 per cent amongst Muslims.

Sixty-four per cent of people said religious leaders like the Pope had a responsibility to speak out on political issues, while 63 per cent said the law should not stop people of faith from expressing their views in the workplace.

The poll also found that men were more likely than women to say their faith did not really influence their life – 53 per cent and 40 per cent respectively.