Cabinet ministers have warned that Downing Street’s current management style and decision-making processes are “unsustainable” and “untenable”, after it emerged that some special advisers have sought counselling due to the stress of their jobs, and others are planning their departures from government.

The scale of unhappiness across government with the Downing Street machine came to light as former special advisers called on senior civil servant Helen MacNamara to defend the workplace rights of ministerial aides.

BuzzFeed News understands that several special advisers have sought counselling and had conversations with MacNamara’s Cabinet Office’s ethics and propriety unit over their treatment at the hands of Number 10. Special advisers have taken to discussing their plans for their next jobs outside of government, with some even talking about walking out en masse.

A source said that civil service officials have become concerned by the behaviour at special adviser meetings in Downing Street, and that non-political officials attending those meetings were now reporting back their worries to senior civil servants.

One senior minister told BuzzFeed News that Boris Johnson must “rein in” his chief aide Dominic Cummings after a series of high-profile bust-ups that culminated in Cummings’ new adviser Andrew Sabisky losing his job over his views on eugenics, which were branded “racist and reprehensible” by Conservative MP Kwasi Kwarteng on Tuesday.

The minister claimed that “half the cabinet” have found themselves unable to work with Cummings since the election and privately hoped that he would leave Number 10 this year. Such is Cummings’ unpopularity across Whitehall that ministers are openly discussing when they think he will leave, with some estimating it could be as soon as next month’s budget, and others saying he could stay for another year.

At a meeting of special advisers before the reshuffle, Cummings provoked outcry when he told government aides that he would “see half of you next week”. The Times reported that ministry of defence adviser Lynn Davidson criticised Cummings for his “unkindness” the following week.

A former government special adviser told BuzzFeed News: “Spads [special advisers] are just a specialised part within the civil service. They are political but they are at the end of the day officials employed by the state not the Conservative party.

“They have the right to work without being bullied or intimidated like any civil servant and the civil service leadership will have to act to make sure that is respected.”

It can also be revealed that special advisers living in fear of losing their jobs have been sending weekly emails to Number 10 reporting on their own ministers and colleagues who have been speaking to journalists, or doing anything perceived as disloyal.

A former special adviser who became aware of the weekly “grassing up” emails compared them to “something done by the Soviet secret police”. “My advice to ministers would be: careful what you tell your special adviser as it could get back to Number 10,” they said.

The former aide also warned that advisers are finding themselves unable to give honest advice to their ministers and to Downing Street, because they are so scared of losing their jobs that they are just saying what they think Cummings wants to hear.

“Ministers who ask small questions of Number 10 or say they don’t agree with one word in a press release are seen as traitors. People fear that if you say the wrong thing you’ll end up like Saj [Javid] and his spads,” they said.

At a separate reshuffle of special advisers last week, aides who were known to be particularly close to their cabinet ministers were moved to different departments because, the former aide said, Downing Street feared they would prioritise their minister over Number 10.

“They broke up the spads who were perceived as too loyal to ministers. Others were told: ‘we could have bulleted you, the only way you’ll stick around if you tell us what’s going on’,” they claimed.

Ministers and their aides have been bewildered that Johnson has allowed Downing Street to brief the media seemingly incorrect stories, while they themselves have been ordered not to speak to reporters. The Times reported on Tuesday that the prime minister did not agree with a Number 10 briefing to the Sunday Times that the BBC licence fee should be scrapped.

Another former aide told BuzzFeed News that government policy announcements and news stories had been overshadowed by rows directly caused by Cummings in almost every week since the election.