Asked about the controversy, Mr Johnson said on Thursday: “It’s a matter for Australia and their friendly government. That’s a matter for them, but clearly I share very strongly their view of the Australian authorities that it’s a very good idea to get vaccinated.”

His response came as Downing Street called for professional sportsmen to get vaccinated. The Prime Minister’s official spokesman declined to comment on specific cases but reissued the call for everyone to get Covid jabs.

The spokesman said: “We absolutely think that everyone should get vaccinated and get boosted, regardless of profession.”

Pushed further on the developments in Djokovic’s case, he declined to comment directly on the incident but noted that UK government scientists had addressed concerns voiced by professional sportsmen.

Dijana Djokovic, the tennis star’s mother, said her son had been subject to a “political attack”, adding: “He is a scapegoat.”