Jeremy Hunt has been branded “utterly ludicrous” for threatening to cancel civil servants’ summer holidays.

The foreign secretary said on Monday if he became prime minister he would order the “ramping up” of no-deal preparations in Whitehall.

Hunt said unless departments could convince him their plans were “on time and on track” he would cancel August leave for officials.

Mark Serwotka, the general secretary of the PCS union which represents civil servants, said officials would “not put up with their leave being cancelled”.

“For a potential prime minister to unilaterally declare that leave for civil servants will be cancelled without consulting them or their union is utterly ludicrous,” he said.

“The government’s handling of Brexit has been shambolic and civil servants have stepped up to the plate on numerous occasions and done their best to prepare for all eventualities.

“Our members working in job centres and other government departments are not responsible for the mess inflicted on them and the country by the sheer incompetence of ministers.”

Garry Graham, the deputy general secretary of the Prospect union, which also represents public sector workers including engineers and scientists, hit out at Hunt for threatening to take away leave for civil servants at the same time as MPs would be on a summer break from the Commons.

“No peacetime government has ever been as reliant on its civil service as this one, and you’d think the Conservative party would be grateful for its work,” he said.

“Instead Jeremy Hunt wants to cancel all August leave for civil servants with less than a week’s notice, at the same time as MPs are going on a five week recess.

“This call for civil service leave to be cancelled smacks of panic and hypocrisy. Politicians would be better placed putting their own house in order and finding a political solution to what is a political issue.”

Hunt said he would launch an all-out diplomatic effort to cut a new deal with the EU if he beats Boris Johnson in the race for Downing Street.

He said he would make a decision on Brexit talks by September 30, ahead of the withdrawal date of October 31.

He said: “It is important that the EU knows that we will do what it takes to make a success of a no-deal Brexit.

“We won’t blink as a country. That no-deal Brexit is not going to be an opportunity for them to successfully turn the screws on our country.”

The Conservative Party will announce the winner of its leadership contest on July 23. 

Parliament is due to recess fore the summer on July 25 and will not return until September 3.