The Birmingham mosque exposed in a Channel 4 documentary as a Mecca for extremist Muslims is being investigated by police after calls from an MP for police to intervene.

The Dispatches programme, broadcast on Monday, showed undercover footage of preacher Abu Usamah calling for gay people to be executed.

“If I were to call homosexuals perverted, dirty, filthy dogs who should be murdered, that’s my freedom of speech, isn’t it?” he told followers.

The controversial preacher was caught on camera at Green Lane Mosque in Birmingham.

He also mocked Western attitudes towards women and attacked Christians and Jews.

Eight MPs have signed an early day motion condemning the preacher’s views.

Labour MP Roger Godsiff wrote to the West Midlands Chief Constable asking for an investigation, and police have confirmed they are studying the documentary.

“I am delighted the police are looking into this. I will see what conclusions they draw,” Mr Godsiff said, according to ITN.

“If the police or Director of Public Prosecutions decide these comments were not racist, I think they are going to have a very difficult time.”

Usamah also called for the creation of an Islamic state in Britain. A spokesman for Birmingham’s Central Mosque criticised Channel 4 for focusing on extremists.