Sorry to disappoint you guys, but Reaction Engines was founded in 1989 (https://en.wikipedia.org/wiki/Reaction_Engines_Limited) and every year they issue press releases stating they are on a brink of revolutionary engine. In this 18 years they didn't produce anything that actually works. Skylon is a "design" [https://en.wikipedia.org/wiki/Skylon_(spacecraft)] and SABRE is a "concept under development" [https://en.wikipedia.org/wiki/SABRE_(rocket_engine)].