Alan Mendoza, President of think-tank Henry Jackson Society, said Britain's minority religions could exert huge influence on next month's election

British Muslims could have the decisive vote in a quarter of constituencies, analysis shows.

In 159 of the 632 seats, the number of Muslims is greater than the margin of victory in 2010.

And this is true among almost half the 193 marginal seats, according to the Henry Jackson Society, which has carried out the first study of the religious breakdown of each seat.

There are also 51 constituencies where the number of Hindus is larger than the winning majority five years ago.

In addition, there are 15 constituencies, all marginal, where the number of Buddhists is greater than the margin of victory and 13 constituencies where the number of Jewish voters is greater.

The HJS, a think-tank, said that, as a result, Britain’s minority religions have the potential to exert a huge influence on the election result.

Executive director Alan Mendoza said: ‘You can suddenly see the changing patterns in terms of religious minority, majority and non-affiliation, and how that plays out on the political landscape.

‘People don’t vote solely on religious criteria but it throws up all kinds of interesting questions about the make-up and influence of constituencies. The findings show how dramatically things have changed when compared to what would have been seen 20 or 30 years ago.’

The HJS analysis came as David Cameron urged black and minority ethnic voters to back the Conservatives, telling them he shares their values.

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The Prime Minister said the Tories had made huge progress in selecting diverse parliamentary candidates, especially in winnable seats, but added: ‘I would say, I know why you have been holding back. I think lots of black Britons look at the values of the Conservative Party and think we agree with you about family and community.

‘The holdback has been people asking themselves if they can get up and get on with the Conservative Party and you can see now that you can.’

In 159 of the 632 seats, the number of Muslims is greater than the margin of victory in 2010, figures show (file picture)

It was put to Mr Cameron that Home Secretary Theresa May – an advocate of reforming stop and search laws – had supported black voters, but Michael Gove had put them off in his role as Education Secretary by pushing for more traditional history lessons. The Voice magazine, which was interviewing the Prime Minister, said black and minority voters wanted lessons to be more ‘diverse’.

Mr Cameron replied that it was ‘sad’ such a view was held about Mr Gove. He added: ‘A lot of black Britons are very passionate about quality in education standards. People who came here from the Caribbean or from West Africa remembered the British education system for its high standards and quality and were a bit disappointed.’

Research by Manchester University revealed earlier this year that in this election, for the first time, the majority of voters in some seats will have been born overseas. There are a record four million foreign-born voters – an increase of 500,000 since 2010 – making up one-tenth of the electorate. Most are from India, followed by Pakistan, Ireland and Bangladesh.