Mr Wallace said non-essential personnel had been moved out of Baghdad while Royal Navy warships and military helicopters were on heightened readiness to assist if needed.

In a Commons statement, he again appealed for all sides to "de-escalate" in the wake of the killing of the Iranian military chief Qassem Soleimani in a US drone strike.

At the same time he defended the right of the US to act in self-defence, saying General Soleimani had been in neighbouring Iraq when he was hit to "co-ordinate murder and attacks on US citizens".

The Royal Navy's Type 45 destroyer will be deployed on escort duties.

Iran launches missile attack on US bases in Iraq

Ahead of a meeting of the National Security Council to discuss the growing crisis, Mr Wallace said the safety and security of UK nationals and interests in the region were of "paramount concern".

Non-essential personnel had been re-located from Baghdad to the military base at Camp Taji, north of the Iraqi capital, while the Department of Transport was reviewing its advice to British shipping on a daily basis.

"At the same time, Defence are changing the readiness of our forces - including helicopters and ships on stand-by to assist if the need arises," he said.

UK F-35 Lightning jets landing, taking off and hovering onboard Britains next-generation aircraft carrier, HMS Queen Elizabeth for the first time.

"As part of prudent planning, a small team has been sent to the region to provide additional situational awareness and contingency planning assistance."

The Government has already announced that the Type 45 destroyer HMS Defender and the Type 23 frigate HMS Montrose are to resume duties escorting shipping through the Straits of Hormuz.

Boris Johnson 'hiding'

In the Commons, Jeremy Corbyn demanded to know why Boris Johnson was not in the House to address MPs, accusing him of "hiding behind his Defence Secretary".

"Isn't the truth that he's scared to stand up to President Trump because he's hitched his wagon to the prospect of a toxic Trump trade deal?" he said.

"Instead, at this highly dangerous moment, we find the Government giving cover and even expressing sympathy for what is widely regarded as an illegal act, because they're so determined to keep in with President Trump."

Speaking to Sky News on Tuesday evening, Mr Corbyn condemned General Soleimani's killing once again.

He said: "To assassinate an official of a foreign government in a third country, in this case Iraq, is illegal under any law and the US, if it wants the world to stand by international law, must stand by international law itself.

"This is a provocative act which has made the whole world a much more dangerous place."

Mr Corbyn was repeatedly asked whether he would label the targeted general as a terrorist. He replied: "Soleimani is the head of special forces of Iran - they obviously operate in all kinds of places that you and I would not agree with or want.

"That is not the point. The point is it's an illegal act that took place and if we want to end illegal acts by anybody; you don't commit them yourself."

The Labour leader later reiterated his criticism of Mr Johnson for failing to address MPs and added: "He is the prime minister of this country, he has to be held to account for what his government says and does; he has to be held to account for his own actions by coming to our parliament to answer questions."

His comments come amid criticism Mr Johnson had been slow to respond to the crisis, not returning from his new year break on the private Caribbean island of Mustique until the weekend.

The Prime Minister's official spokesman said he was continuing to talk to other world leaders and had "overseen the ministerial response" by the Government."The PM leads a Cabinet Government and the response to events in the Middle East is a collective Cabinet response," the spokesman said.

Mr Wallace said Gen Soleimani had been "no friend of the UK" and that the Quds force of the Revolutionary Guards Corps which he led had been "one of the foremost architects of Iran's malign activity" in the region.

"His clandestine operations saw him supply weaponry to proxy forces in Iraq and Afghanistan," he said.

"He encouraged proxies to develop weapons such as improvised explosive devices that killed and maimed UK soldiers and other Western forces."

Mr Wallace said the US believed Gen Soleimani had been behind a militia attack which killed a US civilian contractor in Kirkuk in northern Iraq last month and that he had been in Baghdad to co-ordinate "imminent attacks" on US diplomats and troops."

Since October last year, he said there had been 14 attacks on coalition bases in the country, used by both US and UK forces, and the international "green zone" in Baghdad.

"The UK will always defend the right of countries to defend themselves," he said.

At the same time he said Britain would do all it could to encourage Iran to take a "different path", including working with European allies to "reboot" the nuclear deal abandoned by the US.

"Her Majesty's Government urges Iran to return to the normal behaviour of the country it aspires to be and resist the urge to retaliate," he said.

Iran: Royal Navy warships on high alert as measures taken to protect British nationals