As Jacob Rees-Mogg has pledged to slash 90,000 civil service jobs, his own department has more than doubled since leaving the EU, according to The Telegraph.
The Cabinet Office, run by Mogg, has almost tripled over the previous six years.
The number of employees has risen from 6,000 to around 17,000.
Now the Government is on a collision course with unions and faces the threat of a national strike over controversial plans to axe tens of thousands of jobs in the Civil Service.
Boris Johnson is understood to have told ministers on Thursday that the service should be slashed by a fifth.
Unions reacted with fury, with one leader warning that national strike action was “very much on the table”.
The Public and Commercial Services union (PCS) is to hold an emergency meeting of its executive committee next week to discuss its response.
General secretary Mark Serwotka told the PA news agency that any job cuts would affect anyone relying on public services.
He said: “The Government complains about longer delays for passports and driving licences at the same time as sacking the people who are working so hard to clear the backlog.
“This is not about efficiency. This is about the Prime Minister trying to create a smokescreen to detract from his utter shambles of a Government.
“He has chosen to cause our cost-of-living crisis and is desperate to point the blame somewhere, and he has chosen to point the finger at hardworking PCS members who kept the country running throughout the pandemic.
“Our members will not be the scapegoats for a failing Government. We have our conference in 10 days’ time. Taking national strike action is very much on the table.”
Mike Clancy, general secretary of the Prospect union, said the proposal represented “an outrageous act of vandalism on our public services.”
“Through Brexit, and then the pandemic, we have never been more reliant in peace time on our Civil Service,” he said.
“Our members are highly skilled and there is a real risk to Government delivery from losing their vital expertise.
“The big cuts to public services since 2010 have often proved an expensive error – these proposals risk doubling down on the mistake.”
Dave Penman, general secretary of the FDA, which represents senior civil servants, told PA: “The reason for the Civil Service’s expansion since 2016 isn’t because the Government loosened the purse strings. The Government needed civil servants to deal with the consequences of two unprecedented events: Brexit and the Covid pandemic.
“To govern is to choose and ultimately this Government can decide to cut the Civil Service back to 2016 levels, but it will also then have to choose what the reduced Civil Service will no longer have the capacity to do. Will they affect passports, borders or health?
“Without an accompanying strategy, these cuts appear more like a continuation of the Government’s Civil Service culture wars, or even worse, ill-thought out, rushed job slashes that won’t lead to a more cost-effective government.”
Related: Mogg slammed for turning up to interview with four advisers as he plans to cut civil service