SCOTS cafe owners are backing a Facebook phenomenon encouraging people to give a cup of kindness to a stranger.

Customers ordering lattes and cappuccinos at Stewart's Cafe in Glasgow can also reserve and pay for a second drink for someone who can't afford their own.

The "Suspended Coffee" campaign started in Naples and has filtered through to countries including Bulgaria, the US, Russia and now the UK, thanks to the power of social networking.

The idea is not just aimed at helping the homeless but those who simply are out of work and broke.

Starbucks in the UK has now also backed the idea in principle, by announcing it will take donations for charity and match the cash.

Cafe owners say those taking advantage of the scheme can do so without fear of stigma, as it is not obvious they have received a free coffee.

The Facebook page has designed "Suspended Coffee Supporter" logos for shops to display on their doors.

Frances Brown Stewart, who owns Stewart's Cafe, joined the scheme days ago and put 10 free coffees in the bank. She has already received more than £25 in donations from the public.

She said: "When I saw the Facebook page, right away I thought that's a fabulous idea. We've only been open for eight weeks and were thinking about ways to be more proactive in the community. A lot of people are reluctant to give money as they think it might not be used for that specific purpose.

"This way they know somebody in need is going to get the coffee.

"Now Starbucks has signed up, although it is slightly different, but it's all good.

Stewart suggested there was a wider principle at work than just free coffee. "I think people are recognising that the welfare state is not going to look after them in the same way and we need to take care of others.

"Certainly in Scotland, with all the marches that have been going on, there's a massive feeling of, we have got to take control over this.

"We had a lady in yesterday who didn't know about the scheme but clearly didn't have any money so we were able to give her a coffee and some carrot cake.

"Hopefully more cafes in Glasgow will get involved now."

So far, about 150 British cafes have signed up to the scheme according to the Facebook page, which has about 23,000 "likes".

Patrick O'Donnell, a psychologist at the University of Glasgow, says there could be many reasons for altruism at a time when most people are facing increased hardship.

He said: "What we are seeing is essentially an altruist act but it's relatively minor, quite low cost to the individual and without risk.

"It could be a case of reciprocal altruism: we realise we might need help ourselves at some point and hope somebody would help us back.

"People feel more vulnerable at the moment. If you feel more vulnerable you are more likely to sympathise with more vulnerable people.

"It could also be that the people who are doing this are relatively better off and feel guilty that they are not on the breadline. There is an element of survival guilt. Escaping it can feel like relative success.

"There is another motive for altruism. People want to believe that their gift is making a difference. It's the sense of being able to control things. There are bad things happening but I can make a difference to that.

"What is very clear is that people who have the least give the most proportionately."