London, Jan 04 (Agencies): The number of Britons choosing to become Muslims has nearly doubled in the past decade, according to a study by an inter-faith think tank.

The study by think tank Faith Matters attempts to estimate how many people have embraced Islam.

Despite the "often negative" portrayal of Islam, thousands of Britons are adopting the religion every year, The Independent reported.

Estimating the number of converts living in Britain has always been difficult because census data does not differentiate between whether a religious person has adopted a new faith or was born into it.

Previous estimates placed the number of Muslim converts at between 14,000 and 25,000.

But the new study by Faith Matters suggests the real figure could be as high as 100,000, with as many as 5,000 new conversions nationwide each year.

The researchers used data from the Scottish 2001 census - which is the only survey to ask respondents what their religion was at birth as well as at the time of the survey.

The experts broke down what proportion of Muslim converts there were in Scotland and then extrapolated the figures for Britain as a whole.

In all, they estimated there were 60,699 converts living in Britain in 2001.

The researchers polled mosques in London to try to calculate how many conversions take place a year.

The results gave a figure of 1,400 conversions in the capital in the past 12 months which, when extrapolated nationwide, would mean approximately 5,200 people adopting Islam every year.

The figures are comparable with studies in Germany and France which found that there were around 4,000 conversions a year.

Fiyaz Mughal, director of Faith Matters, said that coming up with a reliable estimate of the number of converts to Islam was "notoriously difficult".

"This report is the best intellectual 'guestimate' using census numbers, local authority data and polling from mosques. Either way few people doubt that the number adopting Islam in the UK has risen dramatically in the past 10 years," he said.

Batool al-Toma, an Irish-born convert who works at the Islamic Foundation and runs the New Muslims Project, a group to help converts, said she believed the new figures were "a little on the high side".

Inayat Bunglawala, founder of Muslims4UK, which promotes active Muslim engagement in British society, said the figures were "not implausible".

"It would mean that around one in 600 Britons is a convert to the faith," he said.