A Fox News reporter is apologising this week after calling an English city "totally Muslim."

Steven Emerson was introduced as a terrorism expert, but admitted he got the facts wrong in his description of Birmingham. 

The West Midlands city has a Muslim population of 22 per cent according to the 2011 census, but Emerson suggested the number was much higher. 

"In Britain, it's not just no-go zones, there are actual cities like Birmingham that are totally Muslim where non-Muslims just simply don't go in," he said during a "Terror in Paris" segment with Jeanine Pirro.

"And, parts of London, there are actually Muslim religious police that actually beat and actually wound seriously anyone who doesn't dress according to religious Muslim attire."

"You know what it sounds like to me, Steve? It sounds like a caliphate within a particular country," Pirro responded. 

Prime Minister David Cameron called Emerson's statements ridiculous. 

"When I heard this, frankly, I choked on my porridge and I thought it must be April Fool's Day," he said . "[T]his guy is clearly a complete idiot." 

Gisela Stuart MP, who represents Birmingham in the House of Commons, was also bewildered by the remarks. 

"I checked whether this was some kind of early April Fool spoof, and then I thought he was talking about Birmingham, Alabama," she admitted. "But then I realised he was just utterly and completely wrong."

Emerson quickly issued apologies on his website and social media. 

"I have clearly made a terrible error for which I am deeply sorry," he said in a statement. "My comments about Birmingham were totally in error. And I am issuing this apology and correction for having made this comment about the beautiful city of Birmingham. 

"I do not intend to justify or mitigate my mistake by stating that I had relied on other sources because I should have been much more careful. There was no excuse for making this mistake and I owe an apology to every resident of Birmingham. 

"I am not going to make any excuses. I made an inexcusable error. And I am obligated to openly acknowledge that mistake. I wish to apologise for all residents of that great city of Birmingham."

Emerson also made a £500 donation to the Birmingham Children's Hospital.