Jacob Rees-Mogg has been condemned for "trivialising bullying" by warning against being "too snowflakey" over complaints against Government ministers.
The top Tory mounted a desperate defence of under-fire Justice Secretary Dominic Raab who is being investigated over a string of bullying claims - which he denies - that reportedly involve at least 24 civil servants.
Rishi Sunak tasked lawyer Adam Tolley KC to launch a probe, which is looking at eight formal complaints during Mr Raab’s stints at the Ministry of Justice, the Foreign Office and the now-defunct Department for Exiting the EU.
But the PM is facing calls to suspend him while the probe is ongoing, with even Tory MPs admitting the row is becoming a "distraction".
The spotlight has shifted to Mr Raab, who also serves as Deputy PM, after Tory chairman Nadhim Zahawi was sacked over his tax affairs at the weekend.
There are also outstanding bullying complaints against ex-Education Secretary Sir Gavin Williamson, who was forced to quit in November after it emerged he'd sent expletive-filled texts to a colleague.
Asked about allegations surrounding both Tories, Mr Rees-Mogg told Sky News: "I think we've got to be slightly careful about the bullying allegations.
"We mustn't be too snowflakey about it. People need to be able to say this job has not been done well enough and needs to be done better.
"It's a very difficult line to judge. It's not a straightforward issue in most cases.
"It's how did somebody react, what did somebody say, is it reasonable to demand from senior and well-paid professionals a level of good service? And then you have to judge whether that line has been overstepped.
"But I do worry we're getting a bit snowflakey about this."
Mr Rees-Mogg said it was "completely sensibly" for the Justice Secretary to remain in post while the investigation is ongoing.
He also backed Boris Johnson for keeping Priti Patel on as Home Secretary despite her being found to have broken the ministerial code over bullying allegations.
But Dave Penman, general secretary of the FDA union which represents senior officials, said: "Even by Rees-Mogg's standards this is outrageous.
"A former leader of the House, trivialising bullying that we know has ruined lives and careers.
"Not only should he be ashamed of himself, but his leader and party should distance themselves from this."
Downing Street distanced itself from the remarks, with the PM's spokesman saying: "I think you see the Prime Minister's views in the action he took."
The spokesman refused to comment on the Raab inquiry while it was ongoing.
Mr Raab is facing calls to quit from his own party as jittery Tories fear the row is becoming a "distraction".
“It just seems to me to be a repeat of the Nadhim Zahawi situation, where it is inevitable that he will be asked to leave the Government,” one ex-Cabinet minister told The Telegraph.
“So why prolong the pain? I think it would be right for Dominic to stand down.”
Another added: “His position is becoming more and more difficult.
"If the Prime Minister is to show his commitment to integrity, Dominic Raab should go while the case is being investigated. He is another distraction.”
But No10 rejected claims it was a distraction, saying the PM was focused on his five priorities, which include small boats and the NHS crisis.
Sir Simon McDonald, a former top civil servant in the Foreign Office, has reportedly given evidence to the inquiry.
He told Times Radio last year that officials working for Mr Raab were “scared to go into his office”, and “felt demeaned” by his conduct.
The Mirror previously revealed that Mr Raab has been nicknamed “The Incinerator” because he “burns through” staff so quickly.
Liberal Democrat Chief Whip Wendy Chamberlain said the scale of the reported allegations raised questions for Mr Sunak.
"Why hasn’t the Prime Minister suspended Raab yet, for the duration of this inquiry," she demanded.
“Rishi Sunak promised to govern with integrity but I’m afraid his track record so far is the opposite.
"Scandal after scandal continues to emerge about various members of the Cabinet, yet Sunak is incapable of doing the right thing and taking decisive action."
Mr Raab has previously defended himself against allegations of bullying, saying: "I've behaved professionally at all times… I look forward to dealing with it fully and transparently rather than dealing with anonymous comments in the media."
No10 has not set a timescale for the conclusion of the inquiry.
