Tributes have been paid to a dedicated teacher who was "marched to death" in sweltering heat as he tried to qualify for the SAS.
The devastated family of Lance Corporal Craig Roberts, who died during an assessment for the Territorial Army's SAS section on the hottest day of the year, said he lost his life "in the pursuit of his dream".
Another unnamed TA soldier also died during the military exercise in the Brecon Beacons on Saturday, as temperatures soared to 29.5C (85.1F). A third man remains in hospital.
One walker said he saw some of the group pleading for water from a colleague.
David Capstick told Channel 4 News: "He was upset.
"The other soldier was trying to make the best of the situation, and asked if we could spare any water for his colleague, not for himself."
He added: "I don't think it occurred to us that fatalities were going to result.
"But it certainly was slightly odd that the two soldiers in particular had bunched together and were clearly in distress. That caused a little bit of alarm among us."
According to Press Association sources, the trio were at the start of an assessment period in the selection process for the TA's section of the SAS, after completing a stint of training and preparation.
Tributes have poured in for Mr Roberts, from Penrhyn Bay, near Llandudno, who worked as a teaching assistant at
Trinity School in Lewisham, south-east London and had reportedly served with the TA for more than five years, including tours of Iraq and Afghanistan.
A spokesman from the school paid tribute to his "dedication, commitment and care" for young people.
He said: "The staff and pupils of Trinity School, Lewisham, have been greatly saddened by the news of the tragic death of Craig Roberts.
"For the past two years Craig worked at Trinity as a teaching assistant and had become a much-loved member of the Trinity community.
"He showed dedication, commitment and great care for young people. In addition to his duties in lessons Craig ran a fitness club, taught Saturday morning revision sessions and helped lead residential trips. He was very committed to the common life of the school."
"Craig was proud of his military commitment and communicated that pride to Trinity pupils. We are pleased that Craig was able to be such a significant part of our community. We pray for him and for his family at this terrible time."
Mr Roberts was due to start work at the Department for Education next month on a prestigious training scheme for "high-flying graduates", the department said.
In a statement issued through the Ministry of Defence, his father Kelvin Roberts said: "We are all devastated at the loss of our beloved Craig; this has left a massive hole in all our lives."
"We wholeheartedly supported Craig in his military endeavours and it gives us some comfort, though great sadness, that he died in the pursuit of his dream.
"Next month Craig was due to start a new post in the office of the Secretary of State for Education and we were all very proud of him."
Friends and pupils have also paid tribute to Mr Roberts, with several pages already set up on social networking site Facebook.
One page described him as a "true gentleman, caring, genuine guy", while in another pupils dubbed him a "one in a million teacher" and said the school would "not be the same" without him.
The MoD has said there are no plans to change "routine exercises" in the rugged Brecon Beacons in light of the incident but the deaths have led to question marks around rigorous SAS training amid concerns by one unnamed army officer that the men were "marched to death" in extreme temperatures.