Rumour has it all is not well with Eidos Montreal’s Thief reboot.

According to Polygon sources, collegial favouritism, office politics, staff turnover, conflicting visions, and a lack of publisher oversight have hampered development of the anticipated title.

One source claimed that incoming lead and senior designers have been scrapping existing stages and mechanics in favour of their own vision for the game.

Another said that the slice of gameplay shown at the Game Developers Conference last month couldn’t run in the game’s heavily modified Unreal Engine 3 environment without non-player character AI switched off and fewer characters than desired on screen at once.

That source also claimed the demo took 10 months to develop – six of which required the participation of nearly every content creator on the team.

It once featured cable TV show-level sex sequences that some animators were uncomfortable creating, the source added.

Another rumour stated that Eidos Montreal was forced to seek out funding from a German investment firm to keep the game's development rolling, something superiors within the studio claimed to be a common strategy in the industry and not cause for concern.

However, it has been claimed that over the past few years, Square Enix has become increasingly concerned with the status of the game, which is now half a decade into development.

Should these rumours be true, the troubles come at a difficult time for Square Enix.

In March, lead game designer Dominic Fleury left the studio – the same month Thief graced the cover of Game Informer magazine.

In addition, sales of marquee franchises Tomb Raider, Hitman: Absolution, and Sleeping Dogs failed to meet expectations, leading the company to report an "extraordinary loss".

That triggered the resignation of company president Yoichi Wada.

Eidos is likely to show Thief publicly for the first time at this year's E3 conference in June.