Ronald Coyne (pictured) has been named as the student who tried to set fire to a £20 note in front of a homeless man

The mother of the University of Cambridge student who was filmed trying to set fire to a £20 note in front of a freezing homeless person tonight described her son's actions as 'thoughtless and cruel'.

Ronald Coyne was seen holding the money after a shocked passer-by watched him allegedly attempt to burn the banknote in front of a vagrant in the early hours of February 2.

Mr Coyne, a distant relative of Scottish First Minister Nicola Sturgeon, was named as the student in the video by the Cambridge University Conservative Association (CUCA).

He was expelled from the group after footage of the prank was seen by hundreds of students when it was shared on Snapchat.

During the video, it shows Mr Coyne, who went to Stewart's Melville - a top Edinburgh school - struggling to set fire to the note while the cameraman pans to the homeless person who is stood outside a Cotswold outdoor clothing shop in Cambridge city centre.

Mr Coyne, from Livingston, West Lothian, can be heard saying 'some homeless shelter' before the video cuts out.

Sandra McLaughlin, 46, the mother of the Pembroke College law student, has said she could not understand her son's behaviour.

His mother said her son spoke to his family following the event and confessed that he had done 'something very stupid' and 'felt really bad about it'.

Speaking from their family home in Livingston, she said: 'I don't recognise that behaviour in my son.

The video shows a homeless man (pictured) standing in Bridge Street in Cambridge city centre clutching what appears to be a sleeping bag

Ronald Coyne, wearing a white bow tie and tails, appears to attempt to burn a £20 note in front of the homeless man

'I don't really know why he's done something so thoughtless and cruel.

'It's completely out of character. He did two years of volunteering at Stockbridge shelter homeless shop in Edinburgh when he was still at school.

'It's very surprising. We're just a normal family. We're not toffs, he's not a toff.

'He's been a hard-working student who is very, very lucky and aware of the privilege he has to study at Cambridge.

'It's been stressful. I'm starting to panic because I can't get a hold of him.

'He spoke to us after the event and said he'd done something very stupid and felt really bad about it.

'He went out a few nights later around Cambridge with one of his friends to do the homeless run and give out tea, coffee and sandwiches to them.

'And this was before the press and ourselves caught on to what he'd done.

'He's obviously known what he's done himself. It's baffling. I've no idea. It's not part of his make-up.

'He's a quiet boy, he wasn't a wild teenager, he was in chess club at school.'

His father, Ronnie Coyne, runs an oil and engineering company, and wrote online that he was 'so proud' of his son after he got accepted to Cambridge.

He wrote: 'Congratulations to my son Ronald Coyne for achieving his tough conditions for Cambridge. I'm so proud of him.'

An extract from his yearbook at Stewart's Melville - where annual boarding fees go up to £21,903 - said he voted 'yes' in the independence referendum.

A spokesman for the CUCA told MailOnline: 'The CUCA committee became aware of serious allegations against Ronald Coyne late last week concerning his private behaviour.

'There is no room for people who behave like that in our association, any other university association, or frankly our university.

Mr Coyne (pictured) went to the Stewart's Melville school in Edinburgh and this is an extract from his yearbook

Mr Coyne (pictured) is a first year law student at Pembroke College and was a member of Cambridge University Conservative Association

'This disgusting and abhorrent behaviour occurred completely independently of CUCA, and did not take place before or after any CUCA event.

'His resignation was immediately demanded and we determined the appropriate response to be to permanently revoke his membership and bar him from all future events, which we did on Saturday.'

Mr Coyne is also believed to be a member of the student Union and the Law Society. He has deleted his Facebook, Twitter and LinkedIn profiles, and his Instagram is now set to private.

Nicola Sturgeon's office said he was not a 'not a direct relative' of the First Minister or her husband but a senior Scottish government source confirmed to the Guido Fawkes blog that he is a 'distant' relative by marriage.

He is believed to be the nephew of the First Minster's sister-in-law's ex-husband.

Speaking to student newspaper The Tab, a Cambridge resident who claimed they saw the Mr Coyne soon after the incident said: 'I was blocked from getting into my college as some chap in white tie was being excluded by the porters.

He was expelled from the CUCA after video of the prank was seen by hundreds of students when it was shared on Snapchat. Mr Coyne is also believed to be a member of the Student Union and the Law Society

'I saw the videos of what he did the next morning, and am utterly shocked and appalled that someone would do such a thing.

'I'm sure I speak on behalf of the student body when I say that we condemn such actions.'

It is rumoured that burning a £50 note in front of a homeless person is one of the initiation ceremonies of Oxford's notorious Bullingdon club.

White tie is the most formal dress code and is usually reserved for high profile events such as state dinners with the Queen, Nobel Prize ceremonies and Magdalene May Ball.

Some members of the CUCA are known to regularly wear white tie to official dinners.

Ex-cabinet minister Ken Clarke is a former chairman, while ex-chief whip Andrew Mitchell and Lord Speaker Lord Fowler are both still Honorary Vice-Presidents.

The Honorary President is prominent historian Andrew Roberts, author of 'Napoleon the Great'.

A Cambridge University spokesman said: 'The University is committed to respecting the rights and dignity of all members of our community.

'We expect our students to treat others with respect, courtesy and consideration at all times, and the University takes allegations of unacceptable behaviour very seriously.

'We do not comment on individual cases.'

Do you know Ronald Coyne? Email Abe.Hawken@mailonline.co.uk