Boris Johnson has been criticised for making a “disgusting” joke that the UK could become the “the Saudi Arabia of penal policy” under Home Secretary Priti Patel.
Opposition politicians said that the Prime Minister had reached a “new low” after footage emerged of the comments made at a Conservative Party fundraiser last week.
Critics argued that the joke was in bad taste because Saudi Arabia has one of the world’s most extreme punitive regimes, including capital punishment by beheading.
Homosexuality is illegal in the Gulf state and can be punished by the death penalty and inhumane sentences such as whippings and chemical castration.
The Business Insider website, which obtained the video, said Mr Johnson made the gag in front of some 300 attendees at the InterContinental London Park Lane hotel in Mayfair.
Kicking off his speech, the Prime Minister said: “In the immortal words of Priti Patel or Michael Howard or some other hardline home secretary, addressing the inmates of one of our larger prisons: it’s fantastic to see so many of you here.”
Mr Johnson went on to tee up the offending joke by discussing the UK’s work on renewable energy.
“I said last year we’re the Saudi Arabia of wind. Probably the Saudi Arabia of penal policy, too, under our wonderful Home Secretary,” he said to laughter from the audience.
In 2011, Ms Patel told BBC’s Question Time programme that she would “support the reintroduction of capital punishment to serve as a deterrent” to “murderers and rapists”.
Attacking the Prime Minister’s comments, Labour deputy leader Angela Rayner said: “Saudi Arabia beheads its own citizens, tortures activists exercising their democratic rights and kills homosexuals.
“This is disgusting. As ever with Boris Johnson behind closed doors the masks slips and we see what he really thinks.”
The Liberal Democrats’ home affairs spokesman Alistair Carmichael said the comment “marks a new low even for” Mr Johnson.
“He may admire his pals in the Saudi dictatorship but with this kind of humour the joke is on all of us,” Mr Carmichael added.
In July, a journalist at the Politico website reported Mr Johnson making a similar joke about Saudi Arabia during a call with business leaders, but was told by Downing Street the suggestion was “total bollocks”.
Following a string of controversies, Ms Patel is widely tipped to be sacked as Home Secretary in the reshuffle on Wednesday afternoon.
Downing Street insisted it has taken a clear position on any human rights abuses committed by Saudi Arabia.
Asked if it was then an odd subject to joke about, the Prime Minister’s official spokesman declined to “get into the details of meetings like that”, adding: “You can see our position is very clear and our record is very clear.”