Phil Spencer, head of Xbox, announces backwards compatibility to play Xbox 360 games on the Xbox One during game publisher Microsoft's Xbox media briefing before the opening day of the Electronic Entertainment Expo, or E3, in Los Angeles, California, Uni

The Xbox One will run an emulator that lets people play their old games without needing to buy them again

Xbox has finally launched backwards compatibility for some Xbox 360 games, so that owners of the current generation Xbox One can play their old games.

The new system will support more than 100 games at launch, with many more being added over time. Members of Microsoft’s early release scheme, Xbox One preview, will be able to try them now and the scheme will be rolled out by the end of the year.

Players won’t have to buy a new version of the game to play it on the Xbox One. If customers have bought a digital copy of the relevant game, then it will just automatically appear, and physical discs can be slotted in and prompt the Xbox One to download the game.

The backwards compatibility doesn’t work by simply playing the game as normal. Instead, Microsoft has built a special Xbox 360 simulator for the new consoles, allowing them to run the games in special software.

The set-up is similar to the way that the Xbox 360 played games from the original Xbox. Microsoft released a — initially only providing support for a few big games like Halo, but eventually expanding to support more than 450 of the biggest games.

Games won’t be added to the backwards compatibility scheme automatically, so users will have to check whether old games are available in the scheme. Instead, Microsoft will work through a list of games, and ask publishers to agree to their games being re-released, making them available for backwards compatibility on an individual basis.

But the 100 games that will be available at launch is likely to cover most of the biggest releases. Microsoft said the system will have over 100 titles “this holiday”, with “hundreds more added in the months to come”.