The Mermaid Conference and Event Centre in Blackfriars, London is to be demolished and replaced with a £250m futuristic hotel, which has been dubbed the ‘Spaceship’. Plans for the distinctive building drawn up by Alsop Architects have been given the go-ahead by the City of London Corporation.

The five-storey, six-star hotel will have a sheer-glass front looking onto the Thames and has been designed to ensure that the views of St Paul's Cathedral remain uncompromised. It will have 251 bedrooms, a two-lane infinity rooftop swimming pool, a spa, bars and restaurants, and extensive banqueting facilities including a 400-person double-height ballroom.

A spokeswoman for the project said: “The scheme will create a landmark stand-alone building that is intended to rejuvenate one of the few remaining major development sites in the City.”

The Mermaid Conference and Event Centre declined to comment on the development, which will see it close after more than 40 years. It was originally named The Mermaid Theatre, and was conceived by the late Sir Bernard Miles. He funded the building by persuading the City of London to donate the site and asking the people of London to give him the money to buy the bricks. The centre, which includes a 600-seat auditorium, underwent a major refurbishment in October 2004.

A hotel operator has yet to be found for the new ‘Spaceship’. Other developments earmarked for the area include the 557ft Jumeirah Tower and the 43-storey Doon Street Tower.