Police have foiled seven terror attacks since the Westminster atrocity in March, Sadiq Khan has revealed.
The London Mayor said counter-terror experts have told him there has been a shift in the threat, rather than a spike in attacks, this year.
There have been five attacks in Britain this year but police have thwarted more over the same period of time.
Mr Khan told a Guardian live fringe event at Labour's party conference in Brighton: "The phrase used by police experts, counter-terror experts, in relation to terrorism is what we're seeing is not a spike but a shift.
"And the reason why they say that is because if you look at the time when Fusilier Lee Rigby was murdered in 2013 up until the Westminster Bridge attack this year, there were 13 terrorist attacks thwarted because of the excellent work of the police and security services.
"If you look at the time between March of this year and now, yes there have been four terrorist attacks (in London) but there have been seven that have been thwarted."
Meanwhile, Mr Khan renewed his attacks on United States President Donald Trump over his so-called "Muslim ban".
"Some of his views are ignorant and I think sometimes people are ignorant, and one of your jobs is to educate people," he said.
"And I'm happy to educate Donald Trump."
The London Mayor also backed "hybrid" shortlists to pick Labour candidates which feature only ethnic minority or women candidates to improve representation in politics.
And he said he would rather be England cricket captain than prime minister, revealing he had unsuccessful trials for Surrey when he was 15 years old, accusing the scout of being "drunk".
"I think England missed out ... it's a miscarriage of justice," Mr Khan joked.
"Had he (the scout) selected me I think we would have had a better last 20 years than we have.
"I'm still reasonably fit, so if anybody in the ECB (England Cricket Board) or whatever (is watching), I'm available."