Residents of Carlisle, Ceredigion, Hackney and Tower Hamlets will be asked to complete a questionnaire on 13 October.

The ONS will use the rehearsal to test some of its systems and processes ahead of the census in 2021, which will be the UK’s first predominantly online census.

The rehearsal questionnaire will be online, with help available for those who need it.

The four areas have been selected for the trial because they include urban, rural and mixed areas with varying internet coverage, Welsh speakers, students and residents with diverse backgrounds.

Pete Benton, director of census operations at the ONS, said: “The census helps inform vital public services such as the number of children’s school places, hospital and GP services and social care provision in local areas.

"As the census only takes place every 10 years it is important we hold an operational rehearsal to ensure that all our processes run smoothly. The people who take part will all be helping to ensure the overall success of the 2021 Census.”

Information on veterans of the UK Armed Forces will be collected during the 2021 census for the first time. The ONS has also proposed to include new voluntary questions on sexual orientation and gender identity, for those aged 16 and over, in addition to the existing question on being male or female.