Britain is braced for a revenge attack from Iran following Donald Trump’s decision to assassinate the nation’s top general.

Security officials fear that UK citizens in the Gulf – or our troops stationed in the region – could be in the firing line.

They are also preparing for a massive cyber-attack to avenge the killing of General Qassem Soleimani. He was blown up by missiles from a US drone after he touched down at Baghdad airport early yesterday morning.

Mr Trump last night claimed that Soleimani was the ‘number one terrorist in the world’ and had been behind attacks in Britain. ‘He made the death of innocent people his sick passion, contributing to terrorist plots as far away as New Delhi and London,’ he said at a press conference.

Angry demonstrate torch US and British flags on the streets of Tehran on Friday after the death of General Qassem Soleimani

An American airstrike on Baghdad airport killed Qassem Soleimani, the head of Iran's powerful Quds force (pictured, the burning remains of a car that was among a convoy the men had been travelling in)

‘We took action last night to stop a war. We did not take action to start a war. We do not seek regime change, however the Iranian regime’s aggression in the region, including the use of proxy fighters to destabilise its neighbours, must end and it must end now.’

The drone strike triggered huge protests in Iran, with demonstrators burning British and American flags and chanting ‘Death to America’.

The Iranian regime vowed last night to exact ‘severe revenge’ for the attack with one hardliner saying ‘Trump and his cronies’ would never sleep comfortably again.

Soleimani’s replacement, Ismail Qani, warned: ‘We tell everyone, be a little patient to see the dead bodies of Americans all over the Middle East.’

British government ministers, military chiefs and security officials were scrambling to work out how to protect the thousands of UK citizens in the Gulf and the troops in Syria and Iraq.

British security officials are preparing for a massive cyber-attack to avenge the killing of General Qassem Soleimani (pictured in 2016)

London was given no notice of the US strike, despite a close alliance with the US and shared military facilities in the region. Officials fear a retaliatory attack by Iranian terrorist proxies or a large-scale cyber-attack to ‘disrupt or degrade’ British interests.

The Government has also not ruled out the prospect of Iran launching a conventional military attack.

UK military bases and Royal Navy ships operating in the Middle East have been placed on a heightened state of alert. Defence planners are reviewing security levels.

Foreign Office travel advice for the region was also under review last night, with the official advice for Iran already updated to urge Britons to ‘avoid any rallies, marches or processions’.

Donald Trump said he did not order the death of Iranian General Qasem Soleimani to start a war but to ‘stop a war'

As UN secretary-general Antonio Guterres urged world leaders to ‘exercise maximum restraint’:

Iran’s supreme leader Ali Khamenei said ‘harsh retaliation’ awaited the US;

Lebanon’s Tehran-backed Hezbollah called on ‘resistance fighters’ to punish the ‘criminal assassins’;

Boris Johnson resisted pressure to fly home early from holiday in Mustique;

Jeremy Corybn was accused of siding with Iran after he criticised Mr Trump;

Motoring groups warned that drivers face paying up to £1 more to fill up after the oil price soared;

The husband of Nazanin Zaghari-Ratcliffe, who is being held in Iran, said he feared for her safety;

The Pentagon said 3,000 extra troops would be sent to the Middle East.

Soleimani spearheaded Iran’s operations in the Middle East as the head of the elite Quds Force. He was widely seen as the second most powerful figure in Iran, behind Ayatollah Khamenei, and has assembled a network of allies across the Middle East.

The Pentagon said Soleimani ‘was planning to attack American diplomats and service members in Iraq and throughout the region’.

It also accused the 62-year-old general of approving violent protests at the US embassy in Baghdad this week.

Secretary of State Mike Pompeo said the strike was ‘wholly lawful’ because Soleimani posed an imminent threat against the US and its interests in the region.

President Trump also taunted Tehran by saying: ‘Iran never won a war, but never lost a negotiation!’

Middle East tension 'will hit fuel prices' Drivers face paying up to £1 more to fill up at the pump due to escalating tensions between the US and Iran, motoring groups warned last night. Fears over the availability of oil in the Middle East could see spooked traders hike prices by 2p a litre, RAC fuel analyst Simon Williams said. It means the cost of filling up a typical 55-litre family car could rise to about £70 for unleaded petrol, and £73 for diesel. The RAC’s concerns were echoed by AA fuel spokesman Luke Bosdet, who warned: ‘Drivers in the UK need to brace themselves for a rise in the price of fuel. With many families looking to pay off Christmas credit card bills, this could make the finances of some more precarious.’ Fears over rising oil prices were worsened after it emerged that dozens of US oil workers were beginning to flee the Iraqi city of Basra, near the border with Iran. The warnings come in a week when fuel prices are already on the rise following four months of falling wholesale prices. Advertisement

The strike did not go down well in world capitals. France’s deputy foreign minister, Amelie de Montchalin, said: ‘Military escalation is always dangerous’.

German foreign minister Heiko Maas said: ‘A further escalation that sets the whole region on fire needs to be prevented.’ UK Foreign Secretary Dominic Raab urged ‘all parties to de-escalate’ and Russian president Vladimir Putin said: ‘This action can seriously aggravate the situation in the region.’

Tom Fletcher, a former British ambassador to Lebanon, said it was ‘hard to overstate the potential impact of this moment’.

On how Iran could retaliate, he added: ‘The strategic response if they’re feeling rational is probably to consolidate their position in Iraq, but elsewhere they have many more dangerous options including assassinations or proxy wars or asymmetric attacks.’

Democratic presidential candidate Joe Biden said Mr Trump had ‘tossed a stick of dynamite into a tinderbox,’ saying it could leave the US ‘on the brink of a major conflict across the Middle East’.

But Republican senator Lindsey Graham said: ‘We killed the most powerful man in Iran short of the Ayatollah. He was the right fist of the Ayatollah and we took the Ayatollah’s arm off.

‘But this is not an act of revenge for what he’s done in the past. This was a preemptive defensive strike planned to take out the organiser of attacks yet to come.’

Ayatollah Khamenei announced three days of national mourning and the country’s top security body said the US would be held responsible for its ‘criminal adventurism’.

In a statement it said: ‘This was the biggest US strategic blunder in the West Asia region, and America will not easily escape its consequences.’ Foreign Minister Javad Zarif called the attack an ‘act of international terrorism’. Iran also has sophisticated cyber-attack capabilities. Tehran could choose a stealth attack that causes maximum damage but with ‘plausible deniability’.

The leader of the Hezbollah militia in Lebanon called for revenge. In a speech yesterday morning Hassan Nasrallah said: ‘To continue on General Soleimani’s path we will raise his flag in all battlefields. Meting out the appropriate punishment to these criminal assassins will be the responsibility and task of all resistance fighters worldwide.’

Lord Ricketts, a former national security adviser, told BBC Radio 4’s World at One programme he thought retaliation was inevitable.

‘It gives the Iranians the option of attacking Western targets right across the Middle East on a timing of their choice ... some kind of target is inevitable.’