Updated

Al Qaeda is building a white army of terror in the United Kingdom, according to the U.K.'s Scotland on Sunday.

According to a source at MI5 — the British equivalent of the CIA — 1,500 white Britons are believed to have converted to Islam with the purpose of funding, planning, and carrying out surprise terror attacks, the newspaper reported.

Click here to read the full Scotland on Sunday report.

Security experts say the growing number of white terrorists poses a serious threat because they are less likely to be detected than members of the Asian community.

Terror groups like Al Qaeda reportedly began recruiting white non-Muslims in response to the success intelligence services have had in disrupting and stopping extremist plots around the world.

One reported strategy the terrorists use is to look for converts in prisons, where those in custody tend to be lonely and particularly susceptible. Recruiters comfort and support the inmate, with little mention — if any — to religion, according to the paper. Over time, conversations turn more radical.

One of leading Muslim leaders disputed the claims of radicalization, saying Islam's strict moral code made it unattractive to many Westerners, the paper reported.