Mark Drakeford says Boris Johnson has no moral authority to lead UK
Boris Johnson has "no moral authority" to lead the United Kingdom, Wales' first minister has said.
Mark Drakeford said the prime minister cannot be asking people to do "difficult upsetting things that you are so patently unwilling to do".
It comes as the prime minister faces renewed pressure over a row about events at Downing Street.
It has been admitted staff gathered inside No10 during the first Covid lockdown to mark his birthday.
ITV News reported that up to 30 people attended the June 2020 event, sang Happy Birthday and were served cake.
No 10 said staff had "gathered briefly" to "wish the prime minister a happy birthday", adding that he had been there "for less than 10 minutes".
The Metropolitan Police has now confirmed it is investigating a number of events at Downing Street and Whitehall.
The comments by Mr Drakeford on BBC Radio 4's Today programme are the latest attack on Mr Johnson by the most senior Labour minister in the Welsh government.
He told the programme: "I just don't think that the prime minister has the moral authority to lead a country like the United Kingdom.
"That's what all this exposes for me.
"You cannot be someone who asks other people to do things, difficult upsetting things, that you are so patiently unwilling to do yourself."
He said he reacted to the latest party row "with a combination of despair and disgust really".
"Despair that this is where our country has ended up after this awful experience. Disgust at the things that went on in Downing Street, and the way that the Tories turn out people to justify it."
He criticised the defence that it only lasted 10 minutes: "You weren't meant to meet for 10 seconds."
A Welsh Conservative MP said toppling the PM now would not be in the national interest.
Preseli Pembrokeshire's Stephen Crabb welcomed the police investigation into the Downing St parties, hoping it would "draw a line" under the affair.
Mr Crabb previously said that Boris Johnson's apology in the Commons may not have been enough.
But speaking on the BBC Two's Politics Live, the former Welsh secretary said he was not close to submitting a letter of no-confidence in the prime minister.
"I think right now is a terrible, terrible time to think about a leadership election," he said.
A leadership contest would create at least one or two months of "sclerosis and gumming up of government".
He added:"I'll be absolutely honest with you. I don't feel as outraged about the report that appeared last night [birthday party] as I did about the allegation of effectively Downing Street being turned into a nightclub on the eve of the Duke of Edinburgh's funeral."
Environment Secretary George Eustice denied ITV's claim that 30 people had gathered in the cabinet room, saying the number of staff present was "closer to 10" and it "was literally just a birthday cake brought in at the end of the day".
Transport Secretary Grant Shapps, whose father was in hospital for four months during the pandemic, also denied as many as 30 had been present, telling BBC Breakfast the group had been working together all day.
He later told BBC Radio 4's Today programme the gathering had been organised by the PM's office but it had been "unwise given the circumstances".
However, despite his own "anger and frustration", he asked for "patience" whilst waiting for the investigation into parties in No 10 during lockdown - lead by senior civil servant Sue Gray - to be published.