Watford Colosseum is to be transformed into a state-of-the-art entertainment venue, after councillors backed plans for a spectacular glass-fronted redevelopment.

HQ Theatres, who run the Wycombe Swan, were appointed as the “preferred bidder” to run the Colosseum five months ago.

Part of that agreement was to refurbish the celebrated music hall, which was shown on BBC2 this week in a documentary featuring the debut performance of the South Oxhey Community Choir in front of a sell-out crowd.

Three “options” for the redevelopment were put to Watford Borough Council's Cabinet, at their meeting inside the venue on Monday.

Option one and two, similar in design except for the placement of a lift and a flight of stairs, proposed a two-storey glass front extension and side extension to provide, at ground floor level, a new box office, cafe and restaurant, new toilets and office space.

An extended balcony, with seating increased from 298 seats to 400, will offer guests on the first floor new toilets and a bar.

The cheaper option three offered the same ground floor improvements with a single storey glass front extension, no lift to the balcony and no additional improvements to the first floor.

The ground floor inside the Colosseum will also be adapted, with raised seats towards the back.

Mayor Dorothy Thornhill said: “It seriously needs money spending on it. We have had an unlucky history with it. Total privatisation didn't deliver and we were left high and dry.

“We have now appointed an operator. Our decision tonight is around how much we're going to invest in the building in order to bring it up to what Watford residents deserve.

“We want it to be a first class entertainment venue and restored to its former glory. In order to do that we have got to spend some serious money. “ Describing the difference between the cheaper and more expensive options, the Mayor added: “It's the difference between adequate and pretty damned good.”

Cabinet members agreed to support option one - an artist's impression can be seen on this page - though this is subject to planning permission and approval from English Heritage.

And councillors were assured developers were committed to not undertaking any changes that would alter the world famous acoustics of the Colosseum.

Though the exact cost of the redevelopment is not known (the press and public were excluded from this part of the meeting as revealing the amount could be “commercially sensitive”), the Mayor told the Watford Observer last month that more than £4million had been set aside for the project, with more cash available if it was needed.