MORE than 400,000 households have yet to return their census forms with only one weekend left until the extended deadline expires.

The National Records of Scotland (NRS) said there had been more than 2m online completions and a further 250,000 paper returns, an overall response rate of 86 per cent.

The NRS target is for a completion rate of at least 85% in each of Scotland’s 32 councils, and a national return rate of 94.2%.

However, seven councils remain below 85%, including Scotland’s largest, Glasgow.

NRS said the completion rate in the city was 79.5% but expected to top 80% this weekend.

Also below target were Dundee (81.9%), Inverclyde (82%) North Ayrshire (84.2%), North Lanarkshire (83.3%), Renfrewshire (83.9%) and West Dunbartonshire (79.6%)

Households which fail to return the once-in-a-decade survey before the May 31 deadline face a £1000 fine.

The census was held in 2021 in the rest of the UK, but delayed by a year in Scotland on the grounds of the pandemic, adding to the pressure on SNP Constitution Secretary Angus Robertson to deliver it.

It was supposed to have been finished by May 1, but Mr Robertson was forced to delay it by a month after a poor response rate.

By the time the first deadline lapsed, only 80% of households had completed it, and there has been only a six percentage point increase since then.

Deputy First Minister John Swinney this week denied Tory claims the census had been “a disaster from start to finish”, and that it was a mistake to separate the Scottish census from those in England and Wales, where the return rate last year was 97%.

Asked if the census could be delayed a second time, the First Minister’s official spokesman said on Thursday that there was no proposal to do so, but added: “Let’s see where we get to in the next few days.”

Intended to help design and improve public services, the 2022 census asks questions on the types of accommodation people stay in, household relationships, age, sex, health and employment status.

New questions this year include use of British Sign Language, passports held, armed forces history and new voluntary questions on sexual orientation and trans status.

Census letters have been issued to more than 2.7m households representing 5.5m people.

A census of the population has been taken every 10 years in Scotland since 1801, with the exception of 1941, because of World War Two.

NRS chief executive Paul Lowe said it was fantastic that the first census to be “principally digital” had seen more 2m households complete their return successfully online.

He said: “With over 89% of census returns being received this way, it reflects the popularity and acceptability of this innovative approach across the nation and will inform how we run the census in future.

“Earlier this week we also crossed a number of milestones, with over 2.2 million household responses received, exceeding an 85% national return rate and 25 local authorities exceeding 85%. I want to thank everyone who has already filled in their census.

“I would urge everyone who has not completed their return to do so now.

“You only have until the end of the month to make sure that your voice is heard. Census data is used to make important decisions on vital public services like schools, hospitals, housing and public transport, so filling it in really makes a difference to you, your family and your community.”

Nicola Sturgeon has said the £150m exercise will be checked by outside experts to determine if it was a “credible exercise”.

Mr Swinney has also promised MSPs that Mr Robertson will update them on the “strength of the information” collected.

A spokesman for NRS said: “A high level of response has already been achieved across the country; we are confident that Scotland’s Census 2022 will provide valuable data for use in service planning. Right now the focus has to be on getting the highest return rate possible because every additional return further improves the result.

“Modern censuses across the UK and in other parts of the world are not just about the census collection, as important as it is, but include further statistical work and a quality assurance process.

"As the First Minister has said, outside expertise will also be sought to provide further reassurance as to the quality of the census and the approaches that are being used.”

As part of its efforts to help people complete the census, the NRS have made almost 1.6m doorstep visits, taken 370,000 calls to the Scotland’s Census contact centre and answered 65,000 emails and web chat enquiries.

Support is available through the website census.gov.scot and on the freephone helpline 0800 030 8308.