The 1921 census has now been released to the public after the documents were sealed for more than 100 years.

The 1921 census holds details about how our ancestors lived and worked in the wake of the First World War and the Spanish flu pandemic.

Taken on June 19, 1921, the records hold information about nearly 38 million people who lived in England and Wales during a period of economic turmoil and when women had just won the right to vote.

Here's what you need to know about viewing the 1921 census online and in libraries.

How to view the 1921 census online

The 1921 census is available online at findmypast.co.uk as well as in person at the National Archives in Kew, the National Library of Wales in Aberystwyth, and the Manchester Central Library.

Findmypast said the 1921 Census will not immediately be free to view - but you can access it via any subscription, including libraries. 

It will only be available via pay-per-view access for the initial period, Findmypast said.

Viewing transcriptions costs £2.50 per record while records can also be viewed as an image of the original document, viewing images costs £3.50 per record.

12-month Pro subscribers via Findmypast can access a 10 per cent discount on all 1921 Census purchases, according to Findmypast.

How can I view the 1921 census for free?

Visitors to The National Archives in Kew will be able to view the 1921 Census online for free via the Findmypast website, the National Archives said.

This also applies to two regional hubs at Manchester Central Library and the National Library of Wales - access will be supported by the Manchester and Lancashire Family History Society helpdesk and the Archives+ Team.

Controversial pay-per-view census decision

Some historians have raised concerns over pay-per-view access to the 1921 census while others looking to analyse their family history complained online.

One Twitter user said: "A bit misleading to advertise about the 1921 census records, but not that they're pay-per-view only. I get that it's an expensive exercise to digitize, but be upfront and transparent."

Another added: "My great grandfather's handwriting has just cost me a fortune in @findmypast costs. Well, that and the poor name variants option. Why isn't the #1921Census free to access? This is public information. I spot another great inequality."

Catherine Warr, the historian behind YouTube channel 'Yorkshire's Hidden History', said it was important to make "history accessible to all".

The historian said: "As a working-class, non-academic historian, I'm passionate about making history accessible to all.

"Whilst there are costs involved in digitising census records and it does involve a lot of work, all that keeping these records behind a paywall does is make it harder for historians and family researchers from lower economic backgrounds to access this information.

"The Welsh Newspaper Archive has managed to make millions of newspapers, from the 19th century to 1918, free for everyone to access, demonstrating that keeping information behind a paywall is a choice, not an obligation.

Swanage and Wareham Voice: Undated handout photo issued by Findmypast Tanya Nakamoto, a Findmypast conservator pushing a trolley of boxes containing some of the 30,000 bound volumes of the 1921 Census, which take up 1.6 linear kilometres of shelving, at the Office for National Statistics (ONS) near Southampton. Undated handout photo issued by Findmypast Tanya Nakamoto, a Findmypast conservator pushing a trolley of boxes containing some of the 30,000 bound volumes of the 1921 Census, which take up 1.6 linear kilometres of shelving, at the Office for National Statistics (ONS) near Southampton.

"If we want to make sure that genealogy and historical research is a welcoming and open hobby for all, we must make it easier for all people to access records - and that means making them free."

Why isn't the 1921 census free?

Findmypast said it had made a "significant investment" in "conserving, digitising, transcribing and building an experience that enables meaningful, accurate searches" of the 1921 census.

The 1921 census saw teams from Findmypast and the National Archives carefully digitise more than 30,000 bound volumes of original documents, all stored on 1.6 linear kilometres of shelving. 

Speaking via the Findmypast website, Findmypast said: "Every page of the fragile physical documents had to be handled by a trained conservation technician who was responsible for a variety of delicate tasks, including removing any objects that could damage the paper, correcting folds covering the text, teasing apart pages that had become stuck together, restoring tears and checking for and repairing other damage."