Neil Basu said teams from the force investigated and prosecuted people behind the threats, which he described as "disgusting and very real".

Asked in an interview with Channel 4 if the threats were credible, the police chief, who is retiring today after 30 years in the force, said: "Absolutely, and if you had seen the stuff that was written and you were receiving it... that kind of rhetoric that is online.

"If you don't know what I know, you would feel under threat all the time."

Asked if there had been a genuine threat to Meghan's life on more than one occasion, Mr Basu, who was until recently the force's assistant commissioner of specialist operations, said: "We had teams investigating it and people have been prosecuted for those threats."

The couple, who stepped back from frontline royal duties two years ago, live in California with their two children.

The duke, who is fifth in line to the throne, is suing the Home Office over its decision not to grant him police protection while he is in the UK.

He had full police protection - generally given to members of the Royal Family - before his departure in February 2020.

In July, the duke won his bid to bring a judicial review into the decision to remove his full police protection.

The review is on the grounds that he should have been informed about the Home Office's security policy before the decision was made.

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No date has yet been set for the judicial review.

Both Harry and Meghan, whose children Archie and Lilibet are sixth and seventh in line to the throne, have previously spoken about threats made against them.

During an interview with Oprah Winfrey in March 2021, the Duchess of Sussex claimed: "It was very clear that the protection of me and or Archie is not a priority, I accept that, but please keep my husband safe.

"I see the death threats, I see the racist propaganda. Please keep him safe."

Prince targeted by neo-Nazi

In 2019, a far-right teenager who accused Prince Harry of being a "race traitor" in an online post was jailed for four years and three months.

Michal Szewczuk, 19, was sentenced at the Old Bailey for the "abhorrent" post, which featured an image of the duke with a gun to his head.

The image showed the royal against a blood-spattered background and included a swastika symbol.

Szewczuk pleaded guilty to two counts of encouraging terrorism and five counts of possession of terrorist material and was ordered to be detained in a young offenders' institution.

Responding to the interview, the Met Police's Commissioner Sir Mark Rowley said: "Neil Basu is an outstanding chief police officer who dedicated his career to keeping London and the UK safe. I wish him well for the future."