A BRITISH man has died while hiking up a mountain in the desert heat in the United Arab Emirates.

Alex Underhill was walking with a friend at the 6,000ft Jebel Jais mountain in the Ras Al Khaimah region when he fell and hit his head.

The 25-year-old, originally from Fareham, Hampshire, but who lived in the UAE, had started to feel faint while they walked in temperatures that peaked at 45C.

The senior manager for the Al Khayat Investment Group died at the scene before rescuers could reach him, according to friend George Crewe.

Describing the events as the "worst day of my entire life", Mr Crewe, from Leicester but living in Dubai, posted on Facebook: "This guy next to me was not only my best friend but he was like my brother, my right arm, my right leg.... we literally did everything together.

"Not many people know what has happened but me and Alex Underhill went hiking at Jebel Jais mountain in RAK. We both got to a certain height and made the decision to turn back as it was so hot and we didn't think we would make it on the water we had left. On the way back down we both felt very faint and exhausted.

"As I was going ahead looking for shaded spots for us to cool down Alex was taking his time sensibly making his way down 10-20 meters behind me.

"After a while I could not hear him so I turned back and I could not see him. I went back to search for him to find that it looked like he had slipped and hit his head and he was unconscious.

"I did all I could do help him and tried to call for an helicopter but we both had no phone signal. I ran to get help and called for a helicopter went with them to find him but before we got there it was too late.

"I am so sorry for everyone's loss, Alex was everyone's favorite person, he will be truly missed. Rest In Peace Alex, I love you so much!"

A Foreign and Commonwealth Office spokesman said: "We are in contact with UAE authorities and providing support to the family of a British man who died in the UAE on 20 June."