Matt McGrath, the "Young Scot of the Year", has revealed that his Edinburgh-based company Aircraft Medical is being pursued in the patent courts by a US rival after Aircraft grabbed one-third of the US market in its first year.

Seattle-based Verathon has launched a patent infringement case in Scotland over Aircraft's portable video-laryngoscope, despite having similar cases dismissed in Seattle and suspended in Atlanta, Georgia, with the US Patent Office declaring all of its claims invalid.

Now at the Court of Session in Edinburgh, Verathon is claiming £37m of lost sales from alleged infringement of its European patent. Aircraft Medical is forecasting $100m (£51.2m) of sales over the next five years from distribution contracts already signed in North America and several European countries, and has had almost 300 approaches from distributors around the world.

McGrath, 30, emerging entrepreneur of the year in 2006 and this month honoured as The Herald's Young Scot of the Year, commented: "Our product is completely different to what is described in their patent, and the £37m is a completely spurious figure. They are obviously nervous of our success, and have come with a very aggressive approach to a new company. It has backfired because the US litigation has been suspended and their own patent is in serious jeopardy."

Verathon began its suit in the US a year before Aircraft Medical even launched its product. The Scottish company is being advised by top international IP lawyers DLA Piper, but there is no provision in the UK for a case to be dismissed at an early stage, forcing the defending company into a long drawn-out and expensive defence.

McGrath added: "They are trying to slow us down, but it is not working. It is quite a big expense, but it is also a compliment. There is absolutely no restriction on the sale of our product anywhere in the world. We are working on making our product number one in the world and it is a very exciting time for us."

Verathon's patent is not only irrelevant to Aircraft's laryngoscope the McGrath, featuring a differently- shaped blade for instance, but it does not even accurately describe its own product the non-portable Glidescope.

McGrath said: "We have had third-party opinions from experts in the US and Europe and received full freedom to operate' reports, which is encouraging but exactly what we knew to be the case.

"In the last five years we have filed 14 patents and design registrations so we have a very strong and growing IP portfolio."

He added: "We are keeping a close watch on our own patents and any potential infringements of those."