Abramovich left feeling blue after cleaners flood his 'secret nightclub'

Building work on a so-called secret nightclub underneath Chelsea Football Club's west London stadium, which is lavishly appointed with a £150,000 waterfall, suffered a serious setback when cleaners inadvertently flooded the venue's hi-tech stage.

The club's £500,000 hydraulic stage was inundated when water seeped through the roof during weekend cleaning of the stadium's east stand.

Jet-powered hoses were being used to wash down the seating area, which lies directly above the nightclub. On Monday, heavy-duty heaters were brought in for emergency drying.

If all goes well, the venue, which was due to open imminently, may not welcome its first guests until shortly before Christmas, when they will encounter its four-metre-high waterfall.

News of the club, said to have "a gritty industrial design motif", didn't emerge until last month, at which point work on the luxuriously fitted space was already at an advanced stage. A former nightclub, Purple which closed in 2007, used to occupy the site.

A source involved in construction at the venue told Building magazine: "You could argue that water seeping in through the ceiling is very much in keeping with the overall gritty industrial design motif the designers are trying to achieve here. It also matches the waterfall.

"There are discussions going on about how best to prevent any future water ingress, but the strategy is to use a mop and bucket when they're cleaning the stand in future, rather than jet-powered hoses."

The new venue is expected to have a capacity for 500. However, those hoping to sip champagne with their favourite oligarch may be a little disappointed. Mr Abramovich has denied that the venue, with its sound system and hydraulic stage, is a nightclub at all, and is in fact a hospitality area for "close friends", though it may be available for private hire.

The venue has its own green room where artists can relax before performances before being hoisted on to a stage via the computerised platform. According to construction industry sources, Mr Abramovich had the idea for the club while on holiday in America. Guests can sit in private booths with their own television screen.

It is likely that the club will be used to entertain friends of Mr Abramovich and his girlfriend, Dasha Zhukova.