"There are 31 marginal seats where the Muslim electorate outnumbers the sitting member of parliament’s (MP’s) majority. In Conservative-held Hendon, for example, the ruling party’s majority is just 1,072. This is in a constituency with an estimated 8,395 eligible Muslim voters. On the other side of the political divide, Labour holds Glasgow North East by just 242 votes. If just a quarter of the 1010 eligible Muslim voters were to swing to the SNP, the Scottish Nationalists would have another seat in Westminster."
This is based on the research released by the Muslim Council of Britain, MCB finds Muslim voters could swing 31 marginal seats, in particular, this listing of constituencies [pdf].
This is a screenshot of the MCB's campaign to register voters:
