British governments blocked two police investigations into the covering up of the killing by British troops of 24 unarmed rubber plantation workers during counterinsurgency operations in Malaysia nearly 65 years ago, the appeal court heard on Tuesday.

Relatives of victims who died in the massacre of Batang Kali in December 1948 were in court to hear how soldiers of the Scots Guards had admitted murdering the plantation workers.

The government intervened to stop a Scotland Yard investigation in 1970 after the soldiers' confession. The police officer in charge subsequently complained that the issue was "politically flavoured from the outset". The investigation was stopped because of a "political change of view" when the Conservatives came to power in 1970, the officer said.

The Ministry of Defence said: "If no reaction is forthcoming, the matter will probably now remain buried in the public mind … and quietly forgotten."

An investigation by the Malaysian police in the 1990s, after fresh evidence emerged, was also blocked following intervention by the British government, the appeal court heard.

One of those killed, Lim Tian Shui, was said to have been found headless. His son, Lim Kok, who was in court on Tuesday to hear the case, said in a written statement: "The British soldiers committed a great wrong. The British authorities committed another [wrong] in the weeks that followed by branding those killed 'bandits' and 'terrorists'."

He said it was at least as great a wrong to maintain that "untruth" for over 60 years.

Relatives of the victims are seeking a public inquiry into the shootings. The British government argues that the UK has no legal responsibility for the acts of the soldiers at Batang Kali.

Scotland Yard files record summary execution by British soldiers in full view of the villagers, Michael Fordham QC, counsel for the victims' relatives told the appeal court.

"There was available evidence both from the Metropolitan police file and from the Malaysian police investigation, and a combination of both, and witness statements," he told Lord Justices Maurice Kay, Fulford, and Rimer.

The government's refusal to hold an inquiry places it in breach of Article 2 of the European convention on human rights convention enshrining the right to life, and of "customary international law," Fordham said.

The victims' relatives are appealing against a high court ruling last year that, since the account of the villagers and five Scots Guardsmen had never been the subject of a definitive inquiry, it was "now impossible to reach any definitive conclusion as to how the deaths of the inhabitants came about".

This ruling was despite the high court judges accepting that claims the Scots Guards were involved in a deliberate execution of the men and that it was covered up by the British army was "a very serious allegation, though one which can properly be made on the evidence".

The high court judges also said it was difficult to escape the conclusion that between 1993 and 1996 departments of John Major's Conservative government decided to "progress any inquiries with as much delay as possible".

A patrol of Scots Guards surrounded and entered the village, north of the Malaysian capital, Kuala Lumpur on 11 December 1948. The male villagers were separated. That evening one of the men was shot by soldiers; the next day a further 23 died. None of the victims were armed and no weapons were found before the killings.

The Malaysian relatives' hopes have been boosted by the British government's decision last year to admit to the torture of Kenyans during the Mau Mau uprising inn the 1950s. Their lawyers also pointed to David Cameron's description in 2010 of the Bloody Sunday shooting by British troops in Northern Ireland in 1972 as "unjustified and unjustifiable", and criticism of Russia by the court of human rights last year for covering up evidence relating to the 1940 Katyn massacre of Polish prisoners.