Jeremy Corbyn has accused Boris Johnson of providing “cover” to Donald Trump over the killing of Iranian general Qassem Soleimani because of his dependence on a post-Brexit trade deal with the US president.

Mr Corbyn branded the drone strike on the leader of Iran’s feared Quds Force an assassination and told the House of Commons that it was widely regarded as illegal.

And he accused the prime minister of hiding away from scrutiny after Mr Johnson sent Ben Wallace, the defence secretary, to answer MPs’ questions on the 3 January killing in Baghdad.

But Mr Wallace dismissed the Labour leader’s comments as “anti-American, anti-imperialistic guff” and insisted that he had seen evidence suggesting there was “a case of self-defence to be made” by Washington, which has claimed Soleimani was involved in the planning of an imminent attack on US interests.

The defence secretary declined to rule out UK involvement in military action in Iran, and said that he hoped British troops would be able to remain in neighbouring Iraq, where their mission training local military forces has been paused following Soleimani’s death so they can concentrate on force protection.

Helicopters and ships in the region have been put on stand-by to assist if needed, while non-essential staff have been relocated from Baghdad to the Taji allied military base, he told MPs in a statement. Meanwhile, a specialist team has been sent to the region to provide additional “situational awareness” and contingency planning assistance.

Calling for a de-escalation of tension on all sides, Mr Wallace told the Commons: “The United States is confident that General Soleimani came to Baghdad to coordinate imminent attacks on American diplomats and military personnel. The UK will always defend the right for countries to defend themselves.”

US airstrike kills Iran's Qassem Soleimani: Fallout in pictures Show all 35 1 /35 US airstrike kills Iran's Qassem Soleimani: Fallout in pictures US airstrike kills Iran's Qassem Soleimani: Fallout in pictures This photo released by the Iraqi Prime Minister Press Office shows a burning vehicle at the Baghdad International Airport following an airstrike in Baghdad, Iraq, early Friday 3 January AP US airstrike kills Iran's Qassem Soleimani: Fallout in pictures The wreckage of the car in which general Soleimani was travelling when a targeted US airstrike struck outside Baghdad International Airport on 3 January Ahmad Al Mukhtar via Reuters US airstrike kills Iran's Qassem Soleimani: Fallout in pictures Demonstrators burn the US and British flags during a protest in Tehran after general Soleimani was killed in a targeted airstrike by American forces Reuters US airstrike kills Iran's Qassem Soleimani: Fallout in pictures A burning vehicle at the Baghdad International Airport following an airstrike. The Pentagon said Thursday that the US military has killed general Qassem Soleimani, the head of Iran's elite Quds Force, at the direction of Donald Trump AP US airstrike kills Iran's Qassem Soleimani: Fallout in pictures Protesters burn Israeli and US flags as thousands of Iranians take to the streets to mourn the death of general Soleimani at the hands of America EPA US airstrike kills Iran's Qassem Soleimani: Fallout in pictures Supporters of Donald Trump pray at an 'Evangelicals for Trump' campaign event held on the day following the killing of general Soleimani. At the event, the president praised the "flawless strike that eliminated the terrorist ringleader" AFP via Getty US airstrike kills Iran's Qassem Soleimani: Fallout in pictures A huge procession of mourners gather in Baghdad for the funeral of general Soleimani on 4 January AP US airstrike kills Iran's Qassem Soleimani: Fallout in pictures Thousands of Iranians take to the streets to mourn the death of Soleimani during an anti-US demonstration to condemn the killing of Soleimani, after Friday prayers in Tehran, Iran EPA US airstrike kills Iran's Qassem Soleimani: Fallout in pictures Iraqis perform a mourning prayer for slain major general Qasem Soleimani of the Iranian Revolutionary Guards at the Great Mosque of Kufa AFP via Getty US airstrike kills Iran's Qassem Soleimani: Fallout in pictures A billboard reading 'Death to America and Israel', installed by Iran-backed shiite armed groups at a street in Jadriyah district in Baghdad, Iraq EPA US airstrike kills Iran's Qassem Soleimani: Fallout in pictures A handout picture provided by the office of Iran's supreme leader Ayatollah Ali Khamenei shows him visiting the family of Soleiman KHAMENEI.IR/AFP via Getty US airstrike kills Iran's Qassem Soleimani: Fallout in pictures Thousands of Iranians take to the streets in Tehran EPA US airstrike kills Iran's Qassem Soleimani: Fallout in pictures Pakistani Shiite Muslims burn a mock of a US flag as they hold pictures of General Qasem Soleimani during a protest against the USA, outside the US Consulate in Lahore, Pakistan EPA US airstrike kills Iran's Qassem Soleimani: Fallout in pictures Iran's Ambassador to Lebanon Mohammed Jalal Feiruznia, looks to a portrait of Soleimani, as he receives condolences at the Iranian embassy, in Beirut, Lebanon AP US airstrike kills Iran's Qassem Soleimani: Fallout in pictures People make their way on the street while a screen on the wall of a cinema shows a portrait Soleimani in Tehran AP US airstrike kills Iran's Qassem Soleimani: Fallout in pictures Aziz Asmar, one of two Syrian painters who completed a mural following the killing of Iranian Revolutionary Guards commander Qasem Soleimani poses next to his creation in the rebel-held Syrian town of Dana in the northwestern province of Idlib AFP via Getty US airstrike kills Iran's Qassem Soleimani: Fallout in pictures A demonstration in Tehran AFP via Getty US airstrike kills Iran's Qassem Soleimani: Fallout in pictures An anti-US demonstration to condemn the killing of Soleimani, after Friday prayers in Tehran EPA US airstrike kills Iran's Qassem Soleimani: Fallout in pictures Mujtaba al-Husseini, the representative of Iran's supreme leader Ayatollah Ali Khamenei, delivers a speech in the holy shrine city of Najaf AFP via Getty US airstrike kills Iran's Qassem Soleimani: Fallout in pictures Pakistani Shiite Muslims burn a mock of a US and Israeli flags as they hold pictures of General Qasem Soleimani during a protest against the USA, outside the US Consulate in Lahore, Pakistan EPA US airstrike kills Iran's Qassem Soleimani: Fallout in pictures Protesters demonstrate in Tehran AP US airstrike kills Iran's Qassem Soleimani: Fallout in pictures Pakistani Shi'ite Muslims hold pictures of General Qasem Soleimani during a protest against the USA, in Peshawar, Pakistan EPA US airstrike kills Iran's Qassem Soleimani: Fallout in pictures Protesters, holding a photograph of the leader of the People's Mujahedin of Iran Massoud Rajavi, outside Downing Street in London PA US airstrike kills Iran's Qassem Soleimani: Fallout in pictures Protesters burn a US flag in Tehran AP US airstrike kills Iran's Qassem Soleimani: Fallout in pictures A Syrian man offers sweets to children to mark the killing AFP via Getty US airstrike kills Iran's Qassem Soleimani: Fallout in pictures Iranian worshippers attend a mourning prayer for Soleimani in Iran's capital Tehran AFP via Getty US airstrike kills Iran's Qassem Soleimani: Fallout in pictures Kashmiri Shiite Muslims shout anti American and anti Israel slogans during a protest AP US airstrike kills Iran's Qassem Soleimani: Fallout in pictures Iranian worshipers chant slogans during Friday prayers Reuters US airstrike kills Iran's Qassem Soleimani: Fallout in pictures A protest against the USA, in Islamabad, Pakistan EPA US airstrike kills Iran's Qassem Soleimani: Fallout in pictures Iranians burn a US flag in Tehran EPA US airstrike kills Iran's Qassem Soleimani: Fallout in pictures Supporters of the National Council of Resistance of Iran in Germany (NWRI) protest outside Iran's embassy in Berlin, Germany Reuters US airstrike kills Iran's Qassem Soleimani: Fallout in pictures Supporters of the National Council of Resistance of Iran in Germany (NWRI) protest outside Iran's embassy in Berlin Reuters US airstrike kills Iran's Qassem Soleimani: Fallout in pictures Iranian worshippers in Tehran AFP via Getty US airstrike kills Iran's Qassem Soleimani: Fallout in pictures Vehicles of the United Nations Interim Forces in Lebanon (UNIFIL) patrol a road in the southern Lebanese town of Kfar Kila near the border with Israel. Following morning's killing of Major General Qasem Soleimani, Lebanon's Iran-backed Hezbollah movement called for the missile strike by Israel's closest ally, to be avenged AFP via Getty US airstrike kills Iran's Qassem Soleimani: Fallout in pictures Iranian women take to the streets in Tehran EPA

Pressed by Mr Corbyn on what evidence the UK had seen to support US claims of a planned attack, the defence secretary added: “From the information and intelligence I have seen, it is clear that there was a case of self-defence to be made about an individual who had come to Iraq to coordinate murder and attacks on US citizens.”

After Mr Trump threatened Iraq with sanctions if its government acted on a vote in the Baghdad parliament and told western troops to leave, Mr Wallace told MPs the UK wants to keep its own military personnel in the country, but was ready to pull out if told to.

“We are ... trying to get them to say that it’s in your best interest for us to remain,” Mr Wallace told the Commons.” [But] we will respect Iraqi sovereignty. If they require us to leave, that is their right and we will respect it.”

Mr Wallace said that the UK would “condemn any attacks on heritage sites” in Iran, adding: “If anyone was to do that, no matter whether they were friend or foe, we would, of course, call them out on doing that.”

Mr Trump declared on Saturday that the United States had identified 52 cultural sites in Iran as potential targets if the conflict escalates, although the Pentagon later indicated the US will observe the laws of armed conflict which outlaw such an attack.

In the Commons, Liberal Democrat acting leader Ed Davey demanded to know if the government could rule out joining the US in any military attack on Iran.

Mr Wallace responded: “I’m not going to rule out anything. The UK will do what it has to do to defend its persons, its citizens and wherever it needs to do that. That is our duty.”

Mr Corbyn demanded to know why Mr Johnson himself had not come to the Commons to deliver a statement on “the assassination of Iranian general Qassem Soleimani – an extremely dangerous and aggressive act that risks starting yet another deadly war in the Middle East”.

The Labour leader said: “He is hiding behind his defence secretary. Isn’t the truth that he is scared to stand up to President Trump because he has hitched his wagon to the prospect of a toxic Trump trade deal.

“At this highly dangerous moment, we find the government giving cover to and even expressing sympathy for what is widely regarded as an illegal act because they are so determined to keep in with president Trump.”

And he added: “Whatever the record of any state official, the principle and the law is that we don’t go around assassinating foreign leaders. Without the clear demonstration of an immediate threat, it is illegal.”

Responding to Mr Corbyn’s demand for Mr Johnson to face MPs, Mr Wallace retorted: “Funnily enough, the prime minister is running the country – something the leader of the opposition will fail to ever do as a result of the election.”

Challenged over why it was Mr Wallace and not the PM himself who was delivering today’s statement to MPs, Mr Johnson’s official spokesman told reporters: “The PM leads a cabinet government and the response to events in the Middle East is a collective cabinet response.”

But Mr Davey said: “It is shameful that Boris Johnson is hiding behind his ministers rather than addressing the intensification of tensions between the US and Iran.

“The prime minister must stop dodging parliament and explain what he will do to de-escalate the situation and ensure the safety of British service personnel and civilians in the region.