Currently, the government advises British citizens against travelling abroad, but Mr Johnson posted on his public Instagram page wearing a face mask in an airport queue, boasting of his arrival into Athens to his 140,000 followers. The social media posts have since been deleted.
Pressed on his father’s journey during an interview with LBC, the prime minister said “you ought to raise that with him”, adding he would not get into the detail of family conversations.
Asked repeatedly whether he was “disappointed”, Mr Johnson replied: “I think the overwhelming majority of the British people have understood what needs to be done and have been very prudent, and that is the right thing to do.”
Ahead of the government publishing a list of countries where British citizens can travel to without facing quarantine restrictions on their return, Grant Shapps, the transport secretary, was also quizzed on Stanley Johnson’s trip to grip.
“The advice says you have to to make your own decision about whether you want to travel,” he said in reference to the Foreign Office advice against all but essential international travel.
“What he won’t be able to ignore, and this applies to everybody, anyone returning to this country from a country not on the list has to quarantine for 14 days.”
He told Sky News: “That would apply to him the same as anybody else who has left this country and is returning. It’s advice, so everyone can decide what to do with the advice. The important thing is that the quarantine is in place.”
Due to Greece’s ban on direct flights to the country from the UK being extended earlier this week, Mr Johnson was reported to have travelled to Athens via Bulgaria.
“I’m in Pelion on essential business trying to Covid-proof my property in view of the upcoming letting season,” he told the Daily Mail. “I need to set up distancing measures at the property because they’re taking it very seriously here.”
He added: “The Greeks are trying to stop bulk arrivals from the UK but they were quite happy to have me coming in. All they wanted to know where I was coming from and what I was doing. Then I had my temperature taken and was swabbed twice.
“We must get these air bridges set up as soon as possible. From what I’ve seen the arrival of the British will not be a danger to the Greeks because they’re so careful here.”
His trip, however, drew criticism from MPs, including Labour’s Rosena Allin-Khan, who said: “Most people have been following the guidelines and socially distancing – not everyone will get a holiday this year.Those closest to the prime minister have different rules though.”
The Liberal Democrat MP Alistair Carmichael added: The Foreign Office currently advises British nationals against all but essential international travel – yet here we see the prime minister’s father flouting these very rules. This is simply further evidence that when it comes to following the rules, it is one rule for the Conservatives and one rule for everyone else.”
The prime minister's official spokesman declined to comment on Mr Johnson senior's trip, but said: "In relation to Foreign Office advice, it is advice and it's for individuals to make judgements themselves."