The mother of an RAF serviceman who vanished on a night out believes he got into a car on the night he disappeared, but said there is "not one shred of evidence" that he is dead.

Corrie McKeague, 23, was last seen in the early hours of September 24 after he had been with friends on a night out in Bury St Edmunds, Suffolk.

His mother Nicola Urquhart, a police officer from Dunfermline, Scotland, said that his abrupt disappearance from CCTV in the town led her to believe he left in a vehicle rather than on foot.

She downplayed the chance of terrorism or a kidnapping but voiced fears her son had been "in the wrong place at the wrong time" and stumbled across something happening.

Praising Suffolk Police detectives' probe into the mystery she said: "Knowing they have done all this work, all I have left is that he left in a vehicle, willingly or unwillingly.

"We can't find one bit of evidence to say that he walked out. Not one bit of corroborating evidence to say that he has been seen anywhere (on foot).

"It only makes sense that he has left, willingly or otherwise, in a vehicle. His own car was only five minutes away."

She added: "Initially, I think - like everybody - we hoped that we were just going to find him; he's been in an accident and he was just going to be found quite quickly.

"As each day goes by and there's no trace of him anywhere it does look more and more like something bad has happened.

"I am a practical person and I do not have one shred of evidence that shows me Corrie is dead.

"So I am going to keep believing that he is alive until we get him back.

"That's the only way we can function. That's the only way we can get through this."

CCTV footage showed Mr McKeague, who was based at nearby RAF Honington, walking alone and eating fast food in Brentgovel Street in Bury St Edmunds at 3.25am.

The serviceman, who had the weekend off, was reported missing on the following Monday September 26, after he failed to turn up for work.

Suffolk Police said on Tuesday they had received a report of possible sighting of Mr McKeague near the Hollow Road industrial estate, heading towards RAF Honington.

Officers were called by a man who told them he had been driving in the area when he spotted a man in light clothing at the back of a sugar beet factory at around 4.20am.

Mrs Urquhart said that she does not "for one second" believe that her son deliberately went Awol.

She has previously voiced fears that a third party may have been involved in his disappearance but police have said they are yet to find evidence of criminality.

She appealed to anyone in Bury St Edmunds on September 23 or 24 to come forward in person or by telephone and email.

She said detectives were starting to use CCTV and other means to check the ownership of all cars in the town around the time of her son's disappearance and people could help by identifying themselves to police.