Two boatloads of refugees exposed an alarming security lapse on British soil today after landing at a military base conducting air strikes against the Islamic State.

The RAF facility in Cyprus was said to have gone into lockdown after nearly 120 migrants, thought to be Syrian, were able to come ashore apparently undetected.

It is the first time since the migrant crisis in the Mediterranean began that they have landed directly on UK territory, just a few hundred metres from the runway used by British fighters jets.

A source on the island accused the Ministry of Defence of allowing the boats to reach the base 'unchallenged' and raised fears they could have been militants from the Islamic State.

Security scare: Images released by the MoD show British troops rounding up nearly 120 migrants after two boatloads of refugees landed at the RAF Akrotiri air base in Cyprus

It is the first time since the migrant crisis in the Mediterranean began that they have landed directly on UK soil

The source told Sky News: 'What if the landing had been of a smaller scale and by members of ISIS, seeking to attack?

'If the MoD can't detect and intercept refugees, there would appear to be a significant vulnerability as yet unaddressed at a time when security and defence are apparently at the fore of the Conservative government agenda.'

The vessels carrying the migrants arrived at RAF Akrotiri, a sprawling military facility used to bomb ISIS targets in northern Iraq, in the early hours of the morning.

ITV news correspondent Emma Murphy, who was waiting to enter the base, said the facility had gone into 'lockdown'.

It was initially reported that four boats had arrived on the island, but this was later revised to two, which were carrying 114 migrants – 67 men, 19 women and 28 children.

British troops talk to two male migrants and a child on the beach at the RAF Akrotiri air base

Cypriot authorities said the two boats were carrying 114 migrants – 67 men, 19 women and 28 children

The MoD expected the migrants to be handed over to the Cypriot authorities once they had been processed

British Bases spokesman Kristian Gray earlier said the authorities haven't established where the boats came from.

The MoD said that it expected the migrants to be handed over to the Cypriot authorities once they had been processed.

'We have had an agreement in place with the Republic of Cyprus since 2003 to ensure that the Cypriot authorities take responsibility in circumstances like this,' a ministry statement said.

The Cyprus Interior Ministry said it was holding consultations with the British High Commission (embassy) on the matter.

Before that deal was signed, migrants landing on the bases had been left in legal limbo.

In 1998, a ramshackle fishing boat crammed with 75 migrants landed at Akrotiri.

Breached: An RAF Tornado fighter jet is seen at the Akrotiri base near the Cypriot port city of Limassol. Two boatloads of refugees have exposed an alarming security lapse after managing to land at the base

Britain's Prime Minister David Cameron meets Royal Air Force pilots, engineers and logistic support staff in front of a Tornado GR4 at RAF Akrotiri, in Cyprus in October last year

Seventeen years on, some of them are still living on another British base on the island after repeated appeals for asylum in Britain were turned down.

The migrants who landed in Akrotiri in 1998 were mostly Iraqi and Syrian Kurds, who had given their life savings to people smugglers to ferry them from Lebanon to Italy.

But the boat's engine sputtered out and the Lebanese crew fled in an inflatable dinghy.

The migrants were moved from Akrotiri to Dhekelia, Britain's largest base on the island, where they were housed in rudimentary, former quarters for British service families that were due to be demolished.

In what was meant to be a temporary measure, they were provided with weekly welfare allowances but 17 years on, 21 of them remain on the base.

Too close for comfort: The migrants boats landed on the shore at RAF Akrotiri, just a few hundred metres from the runway used by British fighters jets that are bombing Islamic State targets in northern Iraq

Cyprus lies just 60 miles from Syria but has so far avoided a mass influx of refugees from the country's war

With children born there and family members who later joined them, they make up a group of 67.

Britain started using RAF Akrotiri to bomb the Islamic State in northern Iraq in September 2014.

Prime Minister David Cameron visited the base two months later to meet pilots, engineers and logistic support staff.

The base is one of two sovereign territories retained by Britain on Cyprus, a colony until 1960.

Despite its proximity to Syria, EU member Cyprus has not seen any of the massive influx of refugees seen by either Italy or Greece, where arrivals have topped 500,000 this year.

Refugees have tended to avoid the island because of its relative geographical isolation from the rest of Europe and difficulties in leaving.