President Trump has said “many” pardons issued by Joe Biden are void because the former president signed them with “autopen” – a device which reproduces a person’s signature – rather than by hand.

Trump did not provide evidence for his claim – which was posted on Truth Social.

BBC Verify has found several instances of Biden signing pardons by hand rather than by autopen.

And a sample presidential signature is used on US government documents when they are stored in the Federal Register – a digital archive. This was the case under Trump as well as under Biden.

Legal experts also told us that there is nothing in US law which would invalidate pardons signed by autopen.

On Truth Social, Trump said that: “The ‘Pardons’ that Sleepy Joe Biden gave to the Unselect Committee of Political Thugs, and many others, are hereby declared VOID, VACANT, AND OF NO FURTHER FORCE OR EFFECT, because of the fact that they were done by Autopen. In other words, Joe Biden did not sign them but, more importantly, he did not know anything about them!”.

Trump didn’t specify which pardons he was referring to but he has previously referred to the house select committee investigating the 6 January riots as the “unselect committee”, and has criticised Biden for pardoning family members.

BBC Verify looked through official photographs of Biden in the White House and ones posted on the official White House X account and found a number of examples of him signing pardons by hand.

In October 2022, Biden was pictured signing an order pardoning those in jail for marijuana possession.

In the same year, he also signed a pardon for non-violent offenders.

It is not known whether Biden has signed any pardons only using autopen.

In May last year, CNN did report that he signed a bill for a one-week extension for federal aviation funding using autopen.

BBC Verify has asked Biden’s office for his record of using autopen and the White House for the evidence behind Trump’s claim.

Trump appears to have taken his cue from the Oversight Project – part of the Conservative think tank The Heritage Foundation – which has claimed that Biden’s 19 January pardons – of some family members and political figures including Anthony Fauci – all had the same autopen signature.

We have asked the Heritage Foundation for its workings. Previously, it has highlighted other Biden documents which it says had autopen signatures, along with screenshots taken from the Federal Register.

The register is the official, daily publication of various presidential and other government documents – which all have a standard signature created from a single sample.

A National Archives spokesperson told the fact-checking website Snopes that: “At the beginning of each administration, the White House sends a sample of the President’s signature to the Federal Register, which uses it to create the graphic image for all Presidential Documents published in the Federal Register,”

We looked through presidential documents archived by the Federal Register under both Trump administrations and found identical signatures on documents.

That includes Trump’s pardons for the 6 January rioters.

Trump had already signed these pardons by hand, as this video showed in January.

Presidential pardons are also published by the US Department of Justice. We have asked it how these documents are archived.

Legal experts who we spoke to told us that there is nothing in US law which says official documents signed by US presidents – including pardons – are not legally binding if they were signed with autopen.

Andrew Moran, a politics professor at London Metropolitan University, says that previous presidents have used autopen before.

“On lower-level importance documents, it’s not unusual for an autopen to be used.

“But I would have thought that with something as serious as a pardon Biden would have actually signed it [by hand]”, he said.

A 2005 memo from the Department of Justice during the Bush administration stated that the President does not have to physically sign a bill for it to become law.

“The President may sign a bill within the meaning of Article I, Section 7 by directing a subordinate to affix the President’s signature to such a bill, for example by autopen”, the memo said.

Although George W. Bush did not use autopen himself, President Obama used it in 2011.

Autopen has also been used by earlier presidents including JFK and Harry Truman.

Professor Erin Delaney, director of the Global Centre for Democratic Constitutionalism at UCL, says that an attempt by Trump to rescind Biden’s pardons would be a “violation of unwritten constitutional norms”.

Critically, he would not be able to pursue this action without prosecuting, or re-prosecuting the individuals who were given immunity, she argues.

Legally challenging Biden’s pardons because of autopen would also call into question other aspects of US governance that use automatic signatures, such as bills passed by Congress and signed into law by the president, she added.

Professor Moran says that a president revoking his predecessor’s pardon is extremely rare.

“Historically, the only example I’m aware of is towards the end of Andrew Johnson’s presidency in the 1860s, when he issued some pardons which were revoked before they were accepted. But that’s a very small number.

“If he [Trump] decides that he wants to go after the people who were pardoned, that will end up in the courts and then that would become the point where the constitution is really tested”, he said.

Additional reporting by Tamara Kovacevic and Shayan Sardarizadeh