A product of Cumnock and the Glasgow district and Scottish Rugby pathway programme, Mark made his professional debut last week for Glasgow Warriors in their Magners League match against Heineken Cup finalists Leinster at the RDS in Dublin.
Commenting on the move, Mark said: “I owe a lot to the coaches who have helped me throughout my early career in Scotland as part of the development programme I have been part of.
“It was a great feeling to make my professional debut with my local club, and I would have been happy to stay in Glasgow, but the opportunity to join Clermont is one I cannot turn down.”
Glasgow Warriors head coach, Sean Lineen, said: “Mark has been one of the stand-out players to have come through our Elite Development Programme, led by Iain Monaghan, this season and his talent has therefore attracted admirers from a number of clubs.
“I’m disappointed not to have Mark in my squad for next season, but I do wish him the very best.
“We have a fantastic group of young Scottish players continuing to come through the Elite Development Programme and I look forward to seeing more of them make the step up to the first team in the future.”
Scottish Rugby’s Director of Performance Rugby, Graham Lowe, added: “Mark is a prime example of the pathway programme in Scotland developing exciting talent and it is no surprise that he has gained admirers beyond our shores.
“It’s a shame he won’t be playing professionally in Scotland in the immediate future, but we will continue to track Mark’s progress and maintain an active role in his development to ensure he has the best opportunity of realising his overarching ambition of playing for Scotland.”