UPDATE 7/11/14 11.30am: Assassin's Creed: Unity, Far Cry 4 and The Crew have now been removed from the US version of Steam. The store's Australian version is also reportedly affected, as are other countries in Europe.
All three titles were available to buy via Steam in the US yesterday, even as Ubisoft confirmed it would not sell them via Steam in the UK.
We've asked Ubisoft for more information on what's going on.
ORIGINAL STORY 6/11/14 11.00am: Assassin's Creed: Unity, Far Cry 4 and The Crew will be unavailable at launch via Steam in the UK.
The three games are listed on the US version of Steam as normal, PCGamesN discovered. But no results pop up if you search for them here in the UK.
All three titles cost $59.99 (around £37.60) on Steam in the US. You can also purchase a Season Pass for Assassin's Creed: Unity and Far Cry 4 for an additional $29.99.
Oddly, it seems to only be Steam that is affected. While Ubisoft would probably prefer you bought the game through its own Uplay store (where it costs £49.99), you can also buy it via third-party retailers such as GreenManGaming (also £49.99) and GetGames (£42.49).
Those prices are more than the typical launch price for a digital copy of a game via Steam.
The just-released Call of Duty: Advanced Warfare is £39.99, for example. The upcoming Evolve is £34.99.
When contacted, Ubisoft declined to give a specific reason for why the game's won't be available in the UK.
"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," a Ubisoft spokesperson told Eurogamer.
"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."