Assassin's Creed Unity, Far Cry 4 and The Crew are all skipping a UK Steam release according to a statement from Ubisoft made over at PCGamesN.
None of the games are listed for a UK Steam release, although they will be available through other UK digital distributors (including Ubi's own uPlay Store), and on Steam in other parts of the world.
Here's the statement from the publisher:
“We've been in discussions with Valve about Assassin’s Creed Unity but for the time being the game is not available via Steam in the UK. In the meantime, UK customers wishing to purchase the game digitally can do so by visiting the uPlay store, our retail partners or other digital distributors.”
As PCGamerN points out, price could be the culprit, with Ubi listing Unity at £49.99 on uPlay and outlets like GamersGate, and £42.99 at GetGamesGo. That RRP's obviously a good tenner past the most expensive games on Steam, which top out around £39.99, although GreenManGaming currently has an 11 per cent discount bringing it down to match that.