An 81-year-old retired academic is seeking to overturn a criminal conviction he received after taking part in an anti-apartheid protest that had been infiltrated by an undercover police officer.

Jonathan Rosenhead is challenging his conviction for a public order offence during a demonstration in 1972. He recently discovered that one of the men who was convicted alongside him was an undercover police officer who was pretending to be a leftwing campaigner.

The spy called himself Michael Scott and adopted a fake identity to infiltrate three leftwing groups, including the Anti-Apartheid Movement, for five years.

Scott’s superiors authorised him to use his fake identity in the criminal trial and to be convicted under his alias.

Rosenhead’s lawyers have written to the Crown Prosecution Service asking for copies of official documents relating to his conviction, which he plans to lodge an appeal against.

The CPS said it believed that there was no reason to overturn his conviction.

His case highlights how a significant number of protesters since 1968 could potentially have been unjustly convicted as key evidence gathered by undercover police officers was withheld from their trials.

So far, 57 campaigners have established in recent years that they were wrongly convicted or prosecuted after discovering their protests had been infiltrated by undercover officers.

An official report commissioned by the government has identified another 83 political campaigners whose convictions could also be in doubt because undercover operations were hidden from their trials.

The 2015 report, by Mark Ellison QC, found that a Scotland Yard undercover unit that infiltrated political groups between 1968 and 2008 routinely ignored legal rules about disclosing the involvement of police spies to criminal trials. He reported that the unit at times failed to correct evidence given in court which it knew was wrong.

Rosenhead, who studied operational research for 50 years at the London School of Economics, was involved in the campaign against apartheid for many years.

In May 1972 he took part in a demonstration against the English rugby team which was about to go on tour in South Africa, at a time when campaigners were pressing for a sports boycott of the apartheid state.

He and the other protesters blocked a coach carrying the team as it left a Surrey hotel for the airport. They left two locked vans and a car at the entrance of the hotel.

Police arrested Rosenhead and 13 others. What he and the protesters did not know at the time was that Scott, one of those arrested, was an undercover police officer.

Scott used his fake identity to infiltrate the Anti-Apartheid Movement, the Young Liberals and the Workers Revolutionary Party between 1971 and 1976.

He was a member of the undercover unit, known as the Special Demonstration Squad, whose members spied on more than 1,000 political groups over 40 years. They developed elaborate fake identities and pretended to be political activists in deployments that usually lasted around five years.

Scott is one of three undercover officers in the unit who are known to have spied on the Anti-Apartheid Movement in the 1960s and 1970s.

A press report from the time recorded that he had told the court that his name was Scott and that he lived in Earls Court, west London. He also said he worked compiling estimates in the construction industry.

Scott was convicted of obstructing the highway and a police officer, fined and given a conditional discharge. Rosenhead was fined the equivalent of £130 in today’s money and ordered to pay another £130 in legal costs for obstructing the highway.

Last year, a judge-led public inquiry that is examining the undercover infiltration of political movements notified Rosenhead of Scott’s true identity.

Rosenhead said: “I think that this unit was out of control. It was violating our human and legal rights.”

A CPS spokesperson said: “We received a request from the defendant’s legal team to review the circumstances of his arrest and conviction after the anti-apartheid protest in Richmond, Surrey, in 1972. The CPS concluded that there is no basis upon which the convictions could be said to amount to a miscarriage of justice.”