Janie Johnson, who writes about ‘Common Sense Conservatism’, tweeted: “My friends just returned from London. Shocked. Hadn’t been in 20 years. Said London is gone – all Islamic.”

Within the tweet, which has now gone viral, Mrs Johnson linked to a news story about a report by the Government’s community cohesion tsar, Dame Louise Casey, on the integration of Muslims in UK communities.

Users hit out at the author, who lives in Nevada, mocking her and taking offence.

Tweeter @tomdavidlarge wrote: “Where’s your evidence. London is a thriving multi-cultural city, in which the only people that aren’t welcome are bigots like you.”

User @torgo added: “Speaking as an American living in London I can tell you this is (xenophobic) nonsense. But I suspect you don’t care to listen.”

And @MsAlliance wrote: “You mean it’s not exclusively white and some people dress and speak differently? We like it like this.”

Others jovially mocked the author for her outrageous tweet, posted on Sunday.

Tweeter @iainmacintosh wrote: “It’s terrible here, Janie. They’ve forced me to wear a burka. It’s actually quite comfy and very warm, but it’s the principle.”

Sharing a photo of the Queen wearing a headscarf, one user wrote: “This is true. I’ve just returned from London, wear [sp] British women are now forced to follow Islamic dress codes.”

Another shared a photo of Mecca Bingo hall and added: “I keep seeing these mosques everywhere. Disgraceful.”

While another simply posted a photo of a salon in Camden named ‘ISIS’ adding: “Yeah that’s correct Janie, I mean even the beauty salons in Camden have been affected.”

But Mrs Johnson appeared undeterred and tweeted that her friends who visited London “are informed people. They were trying to impress upon us how horrible it is. They travel a lot.”