'Twenty Twelve' paints London Games as a five-ring circus

That probably explains “Twenty Twelve,” the gleeful new BBC America sitcom premiering at 8 p.m. Thursday that casts Hugh Bonneville (“Downton Abbey”) as Ian Fletcher, the hapless manager entrusted with coordinating the run-up to the Olympic Summer Games.

Left to his own devices, Ian probably would be a charismatic, competent boss, but this current gig forces him to deal constantly with idiots such as “director of branding” Siobhan Sharp (Jessica Hynes, “Spaced”), who babbles endlessly in PR-speak, and Graham Hitchens (Karl Theobald), who is in charge of coordinating logistics yet incapable of understanding why Ian has qualms about his plan to route all Olympic flights through the airspace above U.K nuclear reactors.

Filmed mockumentary style like “The Office,” “Twenty Twelve” follows Ian and his incompetent staff as they confront increasingly difficult hurdles as the official Olympic clock counts down to the Games — or, rather, counts up, since Siobhan inadvertently has had the thing programmed to count in the wrong direction.

Bonneville, known to zillions worldwide as Robert, Earl of Grantham, in “Downton Abbey,” clearly is having a grand romp in this contemporary comedy, and he is confident it will resonant with most viewers.