At least five British Special Forces commandos have been wounded in gun battles as part of a top-secret UK military campaign in Yemen, The Mail on Sunday can reveal.

The elite Special Boat Service (SBS) troops, whose presence in the war-ravaged country is shrouded in secrecy, suffered gunshot injuries in fierce clashes with Iranian-backed rebel militia in recent months.

The SBS men were treated for leg and arm wounds following the battles in the Sa’dah area of northern Yemen, where up to 30 crack British troops are based. The casualties are understood to be now recovering in the UK.

At least five British Special Forces commandos from the Special Boat Service have been wounded in gun battles as part of a top-secret UK military campaign in Yemen

The revelation that British forces are fighting in Yemen sparked angry criticism last night because the conflict, which has seen Saudi Arabia and Iran support opposing sides in a four-year civil war, has triggered the world’s biggest humanitarian crisis.

Aid agencies have pleaded for a ceasefire to be negotiated to enable charities to help eight million Yemenis facing starvation and two million rendered homeless. An estimated 10,000 people have been killed in the fighting.

MPs have also attacked the Government’s support for the Saudis, who have been accused of war crimes and of deliberately targeting civilians.

The Mail on Sunday can also reveal how RAF engineers sent to Saudi Arabia to repair the kingdom’s fleet of military aircraft narrowly escaped death last week. Iranian-backed rebels launched a ‘suicide drone’ strike on the King Khalid air base, where they are maintaining Tornado jets used to bomb civilian areas in Yemen.

According to reports, the drone exploded on the runway, destroying two Tornados. The MoD said no UK personnel were wounded.

In response to the revelations, former Minister Andrew Mitchell said last night the UK was ‘shamefully complicit’ in Saudi Arabia’s role in Yemen. He called on the Government to provide further explanations to Parliament about the role of the British troops.

The elite Special Boat Service (SBS) troops, whose presence in the war-ravaged country is shrouded in secrecy, suffered gunshot injuries in fierce clashes with Iranian-backed rebel militia in recent months (File photo)

A SBS source said: ‘The guys are fighting in inhospitable desert and mountainous terrain against highly committed and well-equipped Houthi rebels. The SBS’s role is mainly training and mentoring but on occasions they have found themselves in firefights and some British troops have been shot.

‘In a contact a few weeks ago, a SBS guy was shot in the hand and another guy was shot in the leg. Their injuries were a reminder that this is a very dangerous assignment. Obviously nothing about the mission will be confirmed publicly by the Ministry of Defence unless a UK soldier is killed – they’d have to announce that.’

The Government’s official position is that it is seeking a ‘sustainable political solution to the Yemen conflict’.

The SBS men were treated for leg and arm wounds following the battles in the Sa’dah area of northern Yemen, where up to 30 crack British troops are based. The casualties are understood to be now recovering in the UK

Saudi Arabia and its allies in the region are fighting a proxy war against Iran, which supports the Houthi rebels.

The conflict has also seen British Special Forces fighting on the same side as jihadis and militia which use child soldiers. This is because Saudi Arabia and the United Arab Emirates, its main partner in the war, have bribed Yemeni tribal leaders with links to Al Qaeda to take their side in the conflict.

Last night, a former British serviceman who returned earlier this year from Yemen said: ‘These militia follow an Islamic fundamentalist agenda. The tribal leaders accept payments from the Saudis and the UAE in return for youths aged 13 and 14 to bolster the front line. They are poorly armed and have no body armour. So they get picked off by the Iranian-backed rebels.

RAF engineers sent to Saudi Arabia to repair the kingdom’s fleet of military aircraft narrowly escaped death last week

‘It’s not just the odd youth either – child soldiers can make up to 40 per cent of the manpower in these militia units. In spite of their disadvantages, the militia do most of the fighting in Yemen because the Saudi soldiers don’t want to leave their air-conditioned camps.

‘They don’t want to be in Yemen at all. It is the Yemenis who are sacrificing their lives.’

The SBS mentoring teams inside Yemen include medics, translators and Forward Air Controllers (FACs), whose job is to request air support from the Saudis.

Iranian-backed rebels launched a ‘suicide drone’ strike on the King Khalid air base (pictured), where they are maintaining Tornado jets used to bomb civilian areas in Yemen. According to reports, the drone exploded on the runway, destroying two Tornados. The MoD said no UK personnel were wounded

The 200-strong SBS, which is based at Poole in Dorset, is a maritime Special Forces unit and was founded in 1940. It recruits mainly from the Royal Marines. SBS personnel served with distinction in Iraq and Afghanistan and most recently in operations against Islamic State in Syria.

In March 2015, Houthi rebels forced Yemen’s president, Abd Rabbu Mansour Hadi, out of power and into exile. Saudi Arabia saw the rebels as backed militarily by Iran, and began an air campaign in Yemen. The Saudi-led coalition has since received logistical and intelligence support from the US, UK and France.

The coalition has repeatedly been accused by human rights groups of conducting unlawful air strikes on civilian targets. Research from 2016 concluded that more than a third of all Saudi-led air strikes had hit civilian sites.

An MoD spokeswoman declined to discuss the presence of the SBS in Yemen. She added that the MoD took the safety of RAF engineers in Saudi Arabia ‘extremely seriously’ and that suitable and effective precautions were in place.