The first evacuation flights carrying British nationals have taken off from Sudan as UK troops prepare to take over the running of the airfield.

Two Royal Air Force planes have landed at Larnaca Airport in Cyprus as of 6.30am on Wednesday, with the first charter flight back to London set to depart later in the day.

Families with young children were among those on the first flights that landed in Cyprus with a British man telling the BBC that his sister, who left Sudan overnight, felt an overwhelming sense of relief.

Three planes were due to have left conflict-torn Khartoum for Cyprus by Wednesday morning, with Prime Minister Rishi Sunak pledging “many more” would follow as he warned of a “critical” 24 hours.

Defence Secretary Ben Wallace said the UK would take charge of the Wadi Saeedna airstrip near the capital from German forces, after Berlin said its final evacuation flight would leave on Tuesday night.

He said 120 British troops have already been supporting the operation there.

Around 260 people were expected to be flown out overnight on three flights, the first landing on Tuesday evening with around 40 people on board.

British nationals have been told to make their own way to the site with some fearing they will not make it due to a petrol shortage.

The UK military could be ready to use force if needed to protect the air base in the event it comes under attack during the airlift, although the troops are primarily there to help with logistics, the i paper reported.

Mr Wallace told LBC Radio: “The Germans are leaving tomorrow, and we will take over the facilitation at the airfield.

“And the reason the Germans are leaving is people have stopped coming in large numbers.”

He said only one nation can facilitate the airfield at a time, adding: “If the Spanish or the Italians or anyone else wants to fly, we’ll be the ones giving permissions effectively.”

There is “some risk that some of the planes are not full,” he said, as there are “not thousands at the gate” as in the evacuation from Afghanistan.

The Government is considering other options, including a possible seaborne evacuation from Port Sudan, some 500 miles from the capital.

HMS Lancaster and the RFA Cardigan Bay have been sent to the region.

Announcing the completion of Germany’s evacuation efforts, the country’s foreign minister Annalena Baerbock said Berlin would not leave civilians “to their own devices”, in an apparent swipe at the UK’s approach.

She said that “unlike in other countries”, Germany’s evacuation had included all its nationals and not just embassy staff.

There’ll be constant flights within the next few days, but if I can’t find gas to get there, then I’m stuck

Mr Sunak defended the UK’s efforts, saying it was “right” that diplomats were prioritised “because they were being targeted”.

“The security situation on the ground in Sudan is complicated, it is volatile and we wanted to make sure we could put in place processes that are going to work for people, that are going to be safe and effective,” the Prime Minister said at the Foreign, Commonwealth & Development Office (FCDO) crisis centre.

He told teams working on the evacuation efforts that “the next 24 hours are absolutely critical”.

The mission was launched during a ceasefire brokered between the warring factions. But Foreign Secretary James Cleverly warned the extraction of UK nationals is “inherently dangerous” as “we cannot be sure for how long it will hold”.

A UK-born student attempting to flee Sudan said she does not have enough petrol to make the dangerous one-hour drive from the outskirts of Khartoum to the airstrip.

“I’m trying to get there. But the problem is the vehicles that we have have no gas, and the petrol stations are empty,” Samar Eltayeb, 20, from Birmingham, told the PA news agency.

“There’ll be constant flights within the next few days, but if I can’t find gas to get there, then I’m stuck.”

More than 2,000 British citizens have registered in Sudan with the FCDO.

Families with children or elderly relatives, or individuals with medical conditions, will be prioritised for the flights.

Only British passport holders and immediate family members with existing UK entry clearance are being told they are eligible.

Nationals have been warned all travel within Sudan is “conducted at your own risk”.