Embattled Rishi Sunak has come under fresh attack as a union boss claimed civil servants have suffered mental health crises as a result of their treatment by Dominic Raab.
The PM faces calls to sack Mr Raab, who is being investigated over multiple allegations of bullying - which he denies.
FDA boss Dave Penman told Sky News today: "I've spoken to people who are civil servants working and have worked for Dominic Raab, who have suffered mental health crises, have lost their careers essentially because they've had to move and change jobs."
Mr Penman has called for the deputy PM to be suspended while a probe is carried out, stating: "If you're in a workplace where you're being bullied, where the daily grind of coming to work destroys your mental health, then that has an impact on your career".
He rubbished suggestions that Mr Raab was being targeted in a politically motivated attack by civil service "mandarins" as allies of Mr Raab have suggested.
Mr Penman said: "That's extraordinary and it couldn't be further from the truth.
"In actual fact I've spoken to people who didn't raise concerns at the time because they understood the political impact...
"Are we really seeing two dozen civil servants in three different Government departments over a period of four years have got together in some massive conspiracy? That just doesn't sound credible."
Asked why the civil servants waited years to come forward, Mr Penman said: "Because it's really difficult to raise complaints."
Mr Sunak has tasked lawyer Adam Tolley KC with investigating bullying claims against Mr Raab, with dozens of civil servants believed to be involved in eight formal complaints.
Mr Penman called on Mr Sunak to say how much he knew about complaints concerning Mr Raab.
Downing Street has only ruled out the Prime Minister being aware of "formal complaints" as reports suggested he had been warned about his ally's behaviour.
Yesterday Mr Sunak came under attack at PMQs, with Labour leader Keir Starmer branding him "weak".
This morning shadow Levelling Up Secretary Lisa Nandy told Sky News: "If he can't stand up to people in his own cabinet, what hope is there for the British people."
And she added: "The public is paying the price for this Tory psychodrama."
Lib Dem leader Sir Ed Davey also accused the PM of being weak for not suspending Mr Raab.
He said: "I do think in the meantime he (Dominic Raab) should be suspended because the allegations are so serious.
"And again it goes to the weakness of the Prime Minister that he's not prepared to take action when faced with the facts.
"And one of the things we'd like to see is the independent advisor on ethical standards look into what the Prime Minister knew and when with respect to these allegations of bullying against Dominic Raab.
"Did he appoint Dominic Raab knowing these serious allegations were there?"
Yesterday the Prime Minister's press secretary said: "The PM was not aware of any formal complaints at the time of appointing Dominic Raab."
Pressed further, she said: "I don't know what your definition of informal complaints is. The PET (propriety and ethics team in the Cabinet Office) processes are very clear.
"The appointments and usual processes were followed and we were not aware of any formal complaints."
Earlier this week The Mirror reported witnesses also claim the Deputy PM would switch his anger on and off depending on whether it was civil servants or ministers in the room.
Mr Raab's spokesman has previously said he “looks forward to answering the allegations made of him directly”.
Mr Raab insisted last week: “I’m confident I behaved professionally, and of course the Government takes a zero-tolerance approach to bullying.”
