An investigation is under way into how a father and his 16-year-old son drowned on a family scuba-diving holiday in the Mediterranean.
Richard Avent, 58, and son Rhydian got into difficulties about 50ft (15m) down on a dive off Gozo island, near Malta.
His wife, Dr Sian Rees, was also on the dive and helped with attempts to resuscitate them.
Mr Avent, was chief inspector of the assembly government's ancient monuments and historic buildings body Cadw.
The family, from Raglan, Monmouthshire, have two older children who were not on the holiday with them.
Dr Rees, also a senior official with Cadw, is believed to have been planning the holiday with her husband for the past two years.
She is reported to be an experienced diver, but Mr Avent and Rhydian were both novices.
The group had been diving with an instructor for about 10 minutes.
Dr Rees and the instructor had descended to 70ft (21m) while her husband and son stayed above them.
Six minutes later, the instructed signalled to Mr Avent and Rhydian and the pair waved that everything was going well.
'Shocked and saddened'
But minutes later the instructor noticed the father and son were in trouble.
Mr Avent was struggling to push the button which inflates part of the equipment which would have taken the two of them back to the surface.
Father and son blacked out and began to sink before Dr Rees and the instructor brought them to the surface.
The pair were dead when paramedics arrived on the scene.
Welsh assembly First Minister Rhodri Morgan said he was "shocked and saddened" at the news.
He said: "Richard Avent made a massive contribution to the protection and conservation of Wales' most treasured historic sites and buildings.
"His achievements over the past 30 years in the field of archaeology and the historic environment were enormous and he earned an international reputation for his expertise as a champion of Welsh castles.
"Richard's colleagues in Cadw are devastated at his death and I am deeply sorry for their loss.
"I know he was held in the highest esteem by his colleagues for his great knowledge and professional judgement but also for his kindness and wisdom."
Villagers in Raglan described the Avents as a popular couple and Rhydian, a "caring and compassionate" son.
A family friend said: "The whole community is in shock - they are such a lovely, lovely family.
"Sian and Richard were very popular in the village and this tragedy is devastating for everyone."