Ruth Williamson, 34, was one of three Britons and an Australian from a group of 16 killed in a raid that went tragically wrong.

Her uncle, Donald Main, said the family was "devastated" by her "brutal killing".

He said: "Ruth lived and worked in Edinburgh and was a very faithful and diligent visitor of her mother who was in a Perth nursing home for many years.

"She was a wonderful person and had a marvellous, some would say 'wicked', sense of humour. And with more free time in the last two years shehad begun to enjoy overseas travel, particularly to developing countries.

"We have many happy memories of Ruth and it is those that will endure in our minds."

He added that family gave their sympathies to relatives of the other victims and that they hoped to learn more about the circumstances of her death.

There is confusion over whether the security forces or the kidnappers began the shoot-out, where the tourists were reportedly used as human shields.

The other victims were Margaret Whitehouse, from Basingstoke, Hampshire, Durham University maths lecturer Dr Peter Rowe and Australian Andrew Colin Thirsk, 35.

Professor James Stirling: "He was the backbone of the department"

Dr Rowe's colleague, Dr James Stirling, said: "Over the years he produced many research papers and was very much an active member of the group.

"He was also an excellent teacher...he really will be terribly missed. It's a terrible shock."

Explore Worldwide: 12 tourists survived

Dr Rowe's wife, Northumbria University lecturer Dr Claire Marston, 43, is recovering from emergency surgery in an Aden hospital

British diplomat David Pearce said she was "in a very bad way", but out of danger. She was aware that her husband had already died from his wounds.

The remaining British survivors - some named as Gill Dorey, Patricia Morris, Sue Mattocks, Eric Firkins, Brian Smith and David Holmes - are staying at the Movenpick Hotel in Aden and are expected to be flown home on Friday.

Two American tourists and an Australian also survived the attack. All the group had been travelling with British-based company Explore Worldwide.

British consul Penny Walsh said the freed hostages were "holding up as well as could be expected" after their "horrendous experience".

She added: "They have had guns put to their heads and all sorts of things - they have been to hell and back. Two of them have seen their spouses killed."

Human shields

A press conference was held for 10 of the survivors, but most were too shaken by their experience to comment.

British survivor David Holmes summed up their feelings when he said: "I can't believe it, I can't speak."

Security services in the Middle East state have denied that the tourists were killed in a botched rescue attempt.

They said that they only went in after the kidnappers started to execute hostages - starting with Margaret Whitehouse - and that once the shooting had started female tourists were used as human shields.