Civil servants are calling for permission to work a four-day week, saying the move is “critical to attaining a good quality of life” and could help save the Government more than £21 million a year.

The arrangement would more than halve staff turnover and free up money to hire an extra 2,345 workers, officials in the Department for Environment, Food and Rural Affairs (Defra) estimate.

The Public and Commercial Services Union (PCS), which represents civil servants and carried out the research, says it shows sickness absence could also drop from 4.3 average working days lost per staffer annually to 1.5 days.

Whitehall officials are campaigning for Defra to carry out a pilot four-day week scheme within the department so that managers can assess the arrangement.

Statisticians within the department who are members of the PCS say the Government could save £21.4 million from the move.

That figure is based on Institute for Government modelling of the year 2016-17 and updated to reflect a rise in salaries, staff numbers and turnover since then.

In a survey of more than 1,200 members carried out by the PCS as part of its research, 80% of respondents said the change would give them health and wellbeing benefits.

General secretary Fran Heathcote said the study suggested any opposition to employees working a four-day week was “purely ideological” because the arrangement has “financial benefits too.”

“Why else would an employer stand in the way of progress?” she said.

Our members are resolute in their belief that a four-day week is critical to attaining a good quality of life

“Our members are resolute in their belief that a four-day week is critical to attaining a good quality of life, improving their health and wellbeing and helping them to meet caring responsibilities, while all the time increasing their productivity.”

Director of the 4-Day Week Campaign Joe Ryle, who wrote a foreword to the research, said the “time has come” to trial the arrangement in Whitehall.

“As hundreds of British companies in the private sector have already shown, a four-day week with no loss of pay can be a win-win for both workers and employers,” he said.

The Government last week dropped official concerns about South Cambridgeshire District Council’s four-day week after the authority faced opposition from the previous Tory administration.

At Prime Minister’s Questions on Wednesday, Kemi Badenoch attacked Sir Keir Starmer over the move, asking him: “If he is going to bail out the public sector then can he tell us this: does he think it is appropriate – as the Ministry for Housing has done – to approve a four-day week for councils that is not flexible working but is actually part-time work for full-time pay?”

Sir Keir replied: “Questions based on what we’re actually doing are usually better than fantasy questions made up.

“What did they deliver in 14 years? Low growth, a stagnant economy, a disastrous mini-budget, a £22 billion black hole and now she wants to give me advice on running the economy?

“I don’t want to be rude but no thank you very much.”

A Defra spokeswoman said there were no plans for a four-day week.