Naznin Zaghari-Ratcliffe is one of three former political prisoners from Iran and over 100 Iranians living in the UK who have urged the Prime Minister not to get involved in Iran's conflict.
They are all signatories to a letter to Sir Starmer saying that the way to wage war is strengthening the regime in Tehran.
The letter acts as a counterpoint to those in the diaspora who support Reza Pahlavi, the exiled son of Iran's former pro-Western monarch, and are backing attacks on Iran as a precursor to regime change. Pahlavi has offered to lead a democratic transition but Trump has said he is looking for an internal candidate to lead the Middle Eastern country.
The letter says: "No one can say they want to end the Islamic Republic more than we do. But waging war on the country in this way will have the opposite effect. It will strengthen the authoritarian and revive the fiction that has sustained their domestic support for decades: they are fighting Western imperialism."
When Netanyahu - a man accused of international war crimes for killing countless civilians in Gaza - kills the dictator of Iran, it kills a man but immortalises the myth. Iranians wanted him to be tried and punished for his crimes, not given an end he wanted."
The 86-year-old Supreme Leader, Ali Khamenei, was killed by Israeli air strikes on the first day of the war, along with his family. He was replaced by one of his sons, Mushen Khamenei.
The group in the letter outlines a series of peaceful and practical steps to help the domestic opposition, including providing Starlink to end the communications blackout in Iran.
Zaghari-Ratcliffe, a dual citizen, spent six years in Tehran prison on espionage charges from 2016. Other signatories include Iranian political prisoner, Rasi Amir, a former British Council employee who spent three years in Evin prison in Tehran, and Nasrin Parvaz, who spent eight years in Iranian prison from 1982. Others are prominent artists in Iranian society, as well as academics and writers.
They write: "Pro-democracy policies would protect political prisoners and ensure that Israel and the US do not bomb prisons like Evin. It is in these cells that the future democratic leaders of Iran reside. Pro-democracy policies would smuggle internet devices - not weapons - across the border and break the blackouts that cover the country. Pro-democracy policies would draw Israel out of its policy of murder even when it targets leaders we despise. There is so much that can be done in solidarity with Iranians. But joining Netanyahu's endless wars is not."
Starmer has changed his policy on collaborating with a US attack on Iran, saying it was necessary to prevent Gulf states from being attacked by Iran.
The Iranian group in the letter say they are "overwhelmed with grief. For decades, we have hoped for the day when Iranian democracy would finally flourish. Many of us have been unable to visit Iran for years because of arrest or worse fear."
And they criticise the Israeli leader, saying that racism was the basis of his policies when he urged Iranians, "Don't sit with your arms crossed, get up and do the work." They reject the assumption in his comments that "90 million people have been waiting for decades for his bombs."
They add: "Of course, this is not just Netanyahu's war, Trump and the US are a significant part of it. But as US Secretary of State, Marco Rubio, said: "The President has made a very prudent decision - we knew that Israel's action would be, we knew that it would provoke an attack on American forces, and we knew that if we did not act preemptively against them before they began these attacks, we would suffer more casualties." So the US has followed Netanyahu into war."
