Protesters have staged a mock execution as they entered the final day of their hunger strike outside Downing Street in a bid to pressure the UK government into condemning the “horrific” executions being carried out in Iran.

The three-day demonstration began on Saturday to coincide with the anniversary of the massacre of around 30,000 political prisoners across the country in 1988.

Iran’s supreme leader at the time, Ayatollah Ruhollah Khomeini, issued a secret fatwa against people deemed to be “at war with Allah”.

During the five-month purge the majority of people executed came from the main political opposition party, the People’s Mujahedin of Iran, and other smaller left-wing groups such as the Iranian Communist party.

Many were members of the minority Sunni Islamic community.

Over the weekend groups of Anglo-Iranians and British supporters marked the anniversary in protest over the more than 2,500 people they say have been hanged in the country since the start of Hassan Rouhani’s presidency in 2013.

The National Council of the Resistance of Iran, which organised the protest, said: “The hunger strikers and protesters are urging the UK government to categorically condemn the incessant cruel hangings that are taking place unabatedly in Iran and act with its Western allies to press for an immediate halt to the executions and torture in Iran.

Human rights attacks around the world Show all 10 1 /10 Human rights attacks around the world Human rights attacks around the world China Escalating crackdown against human rights activists including mass arrests of lawyers and a series of sweeping laws in the name of ‘national security’. Getty Images Human rights attacks around the world Egypt The arrest of thousands, including peaceful critics, in a ruthless crackdown in the name of national security, the prolonged detention of hundreds without charge or trial and the sentencing of hundreds of others to death. Getty Images Human rights attacks around the world Gambia Torture, enforced disappearances and the criminalisation of LGBTI people; and utter refusal to co-operate with the UN and regional human rights mechanisms on issues including freedom of expression, enforced disappearance and the death penalty. Getty Images Human rights attacks around the world Hungary Sealing off its borders to thousands of refugees in dire need; and obstructing collective regional attempts to help them. Getty Images Human rights attacks around the world Israel Maintaining its military blockade of Gaza and therefore collective punishment of the 1.8 million inhabitants there, as well as failing, like Palestine, to comply with a UN call to conduct credible investigations into war crimes committed during the 2014 Gaza conflict. Getty Images Human rights attacks around the world Kenya Extrajudicial executions, enforced disappearances and discrimination against refugees in its counter-terrorism operations; and attempts to undermine the International Criminal Court and its ability to pursue justice. Getty Images Human rights attacks around the world Pakistan The severe human rights failings of its response to the horrific Peshawar school massacre including its relentless use of the death penalty; and its policy on international NGOs giving authorities the power to monitor them and close them down if they are considered to be “against the interests” of the country. Getty Images Human rights attacks around the world Russia Repressive use of vague national security and anti-extremism legislation and its concerted attempts to silence civil society in the country; its shameful refusal to acknowledge civilian killings in Syria and its callous moves to block Security Council action on Syria. Getty Images Human rights attacks around the world Saudi Arabia Brutally cracking down on those who dared to advocate reform or criticise the authorities; and committing war crimes in the bombing campaign it has led in Yemen (pictured) while obstructing the establishment of a UN-led inquiry into violations by all sides in the conflict. Getty Images Human rights attacks around the world Syria Killing thousands of civilians in direct and indiscriminate attacks with barrel bombs and other weaponry and through acts of torture in detention; and enforcing lengthy sieges of civilian areas, blocking international aid from reaching starving civilians. Getty Images

“They also called on the UN Human Rights Council and the UN Security Council to refer the human rights dossier of the mullahs’ regime to the International Criminal Court for the prosecution of its leaders including the Supreme Leader Ali Khamenei and President Hassan Rouhani.”

The Paris-based group’s president-elect Maryam Rajavi described the 1988 massacre as an “appalling crime against humanity” and said it was time for the UN “to end their silence and bring the record of the Iranian regime's crimes before the International Criminal Court.”

Conservative MP Matthew Offord offered his support to the protesters saying: “I would like to send my best wishes to all of you who are protesting against the horrific events we have seen happening in Iran over this past few weeks.

“The mass execution of Sunni political prisoners is deeply disturbing and has rightly been condemned.

“A few weeks ago, I spoke to over 100,000 people who attended the annual National Council for Resistance in Iran conference in Paris.