We now know that in the past Sadiq Khan, who as a left-wing human rights solicitor represented Muslim extremists, was happy to make compromises with the Salafist attitudes that prevail in many London mosques. In 2004, he supported incorporating sharia law into the British legal system: “There are some . . . uncontroversial areas of Islamic law which could easily be applied to the legal system . . . in the UK.” What Khan had in mind by “uncontroversial” was the legitimisation of polygamy, by altering inheritance tax law to allow husbands to divide their estates between several wives while enjoying the tax exemption normally applicable to a single spouse. He called this “applying common sense”, but it was yet another step towards de facto recognition of polygamy by the law. Muslims have long been claiming welfare benefits for multiple wives; the only condition is that they must have married them abroad.

In 2007, Khan questioned the need for the criminal law to be used to stop forced marriages, claiming that such “ghetto” legislation would stereotype Muslims. Of course, he glossed over the fact that forced marriage was almost exclusively a Muslim problem in Britain. It is hard to avoid the conclusion that Khan is a typical left-wing cultural relativist — and they are a big part of London’s problem. Despite having made his career as a human rights lawyer, Khan has never challenged the conspiracy of silence about certain offences — such as forced marriage and abduction, female gentile mutilation and “honour crimes” — that are committed mainly by Salafist and other fundamentalist Muslims on a huge scale, yet are rarely or never prosecuted in Britain. Nor did he expose grooming by Muslim gangs.

Under Mayor Khan, London will undoubtedly deserve more than ever the ironical nickname it earned a decade ago among European intelligence services: “Londonistan”. It is hard to imagine Khan taking the tough measures to root out Isis cells hidden inside Muslim ghettos that have been forced on French and Belgian police forces since the attacks on Paris and Brussels. Even in the aftermath of a similar attack on London, it is inconceivable that Khan would risk the accusation that he had turned his back on his Muslim heritage. His opinions change according to need; his allegiance doesn’t.

In policing, Khan is far more likely to attach weight to the “sensitivities” of Muslim community leaders than to put pressure on those communities to eradicate radicalisation. According to ICM, only a third of Muslims say they would inform police if they thought someone was involved with terrorist groups in Syria. The Metropolitan Police have searched London mosques on very few occasions. They would be more proactive if they felt that the mayor would back them in upholding the law. Fear of causing offence explains the failure to protect minorities who are unpopular with the Sunni majority. After an Ahmadi newsagent was killed in Glasgow in March, it emerged that a Pakistani group urging Muslims to murder members of the Ahmadiyya sect has close links with a Deobandi mosque at Stockwell in South London where their leaflets were found, though a mosque trustee denied any knowledge of such links. The same concerns apply to London’s 40-odd universities. It is rare for police to intervene to preserve free speech on campus, or for a university to clamp down on intimidation by an Islamic society. Yet terrorists and IS recruits include a high proportion of students and graduates, including doctors and engineers. I cannot imagine Mayor Khan standing up to such powerful lobbies as London’s universities and mosques, even after a major attack.