When city councillors meet on Thursday to decide the future of the Marlowe Theatre it will be the biggest decision, they will ever take, says council chief executive Colin Carmichael.

He was speaking ahead of a meeting of the full council when members are expected to approve the £25.6 million rebuilding of the theatre.

“This is one of the biggest things this council has ever done,” Mr Carmichael said, “and it’s probably the biggest decision these councillors will ever have to take.”

Before them are three options: Demolish and rebuild the theatre; refurbish the existing building at a cost of £19.8 million or close it outright at a cost of £5.5 million.

Council members have been broadly supportive of the first option which would see a 1,200-seat circular auditorium, a 150-seat second space for smaller performances plus workshops, three foyers and bars and a riverside walk and cafe.

When complete, the building will resemble the Wexford Opera House in Ireland which opened in October.

Keith Williams, the 2006 winner of public building architect of the year, is the designer on both projects.

Janice McGuiness, the council’s head of culture, said: “The aim is to create a landmark building in the centre of Canterbury.

“The current building is completely inadequate.

"It has worn out plant and equipment and inflexible seating which means people can be up to 35 metres away and that meant that we miss out on a lot of top class shows like Miss Saigon which we were not able to put on.”

The building is a former cinema built in the 1930s and was converted into a theatre in 1984.

The city council will put at least £15.3 million of local taxpayers’ money into the scheme with the rest coming from the county council, the South East England Development Agency, other contributions and a fund-raising drive which starts later this month.

Mr Carmichael insists the cost of the project is reasonable, saying that the tenders they had received for the work are “very good”.

And he says the theatre will be used for a variety of different purposes and at the heart of the city and community.

He said: “The right thing to do is to continue to invest in Canterbury.

“Some people who have seen the plans may not like them, but then again there were probably people opposed to the addition of the Bell Harry tower on the Cathedral.

“Every century has left its mark on Canterbury and we feel it’s important that the 21st century also does.”

The council’s ruling executive backed the scheme at a meeting on Tuesday night and passed it to the full council for a final decision.

If approved, the theatre will shut with a 'Night of a Thousand Stars’ on Sunday, March 22.

The former Friars garage, which forms part of the proposed new site, will be demolished and then work will start at the end of April.

The new Marlowe Theatre is due to open in September 2011.