The government has urged Whitehall bosses to “move quickly” to get more staff back into the office.

In a letter seen by the BBC, it says it is “strongly encouraging” attendance through rota systems, arguing this would be “hugely beneficial”.

The government says it wants 80% of civil servants to be able to attend their usual workplace at least once a week by the end of the month.

But unions have described the government’s attitude as outdated.

They say most civil servants should expect to keep working from home until the end of the year and that they fear an increased risk of catching coronavirus when back with colleagues.

The letter applies to staff in England, with those elsewhere in the UK expected to follow local guidance and continue working from home.

It follows criticism that too few civil servants working from home because of coronavirus have returned to their desks, despite the easing of lockdown.

Analysis of mobile phone data last month suggested only 17% of UK workers had returned to the office.

The government was expected to launch a campaign to encourage people back to the workplace after business leaders, including the head of the Confederation of British Industry (CBI), warned that city centres could become “ghost towns”.

Thousands of businesses that rely on passing trade are suffering while offices stand empty, Dame Carolyn Fairbairn from the CBI has said.

But Alex Brazier, the Bank of England’s executive director for financial stability, has warned that the government should not expect a “sharp return” to “dense office environments”.