Writer and performer Robert Webb wrote on Twitter: "Well, it's a beautiful day here in Trump's war zone. I've been to the shop and didn't get even mildly stabbed. Now we're nicely stocked up on tinned goods & I won't have venture out again till Tuesday. Phew!"

According to the BBC, Trump may have used as inspiration a Radio 4 interview last month with a London trauma surgeon, Martin P. Griffiths, who said he was treating stabbing victims "on a daily basis."

But the surgeon, who works for the Royal London Hospital, responded on Twitter to Trump, suggesting he had missed the whole point and saying he was "happy to invite Mr. Trump to my (prestigious) hospital."

Karim Brohi, a trauma surgeon at the Royal London Hospital, said in a statement on Saturday that while knife violence was "a serious issue" in London, "to suggest guns are part of the solution is ridiculous."

Knife crime in Britain rose by 21 percent last year, according to figures released in September by the Office for National Statistics, and stabbings in London were at their highest level in six years. At least 38 people in London have died from knife crime so far this year, police said.

At the National Rifle Association gathering on Friday in Dallas, Trump suggested that guns are part of the solution to knife crime in London.

He said Britain has tough gun laws but that one London hospital has "blood all over the floors" because of knife wounds.

Karim Brohi, a Royal London surgeon, tweeted that Trump's remarks were "ridiculous".

Martin Griffiths, a surgeon at the Royal London Hospital, tweeted on Saturday he would be "happy to invite Mr Trump" to visit his hospital and meet with London's mayor and police chief to learn how the city has reduced violent crime.