also placed on the roof. The exterior consisted mainly of the glass slabs and projecting air handling units with recessed windows. Redevelopment 1997 The Royal Mail sorting office was recognised by Chatham in 1997. Chatham had been an important figure in the regeneration of Birmingham, working with Argent to develop Brindleyplace. He found out that the sorting office was to be sold and tried to convince Argent about the potential the building offered if it were to be converted into a mixed-use building. Argent was unconvinced and so Chatham decided to establish his own development company, Birmingham Development Company, and purchased the building in 1998 for £3 million. He also paid a further £1 million for the surrounding waterfront buildings. Soon after purchasing the building, he sold the air-rights to Crosby Homes, providing him with further money for redeveloping the building. The building was converted by the Birmingham Development Company and designed by the RIBA award winning, Birmingham practice, Associated Architects. It was to include two hotels with a total of 300 rooms, 15,850 sq. m (170,000 sg. ft.) of office space, 9,290 sq. m (100,000 sq ft.) of retail space and a similar area for restaurants and a health club. Crosby Homes constructed apartments above the space. The redevelopment of the sorting office involved demolition of all but the steel sub-structure. It cost £150 million overall and opened in December 2000. Following the purchase of two retail units by Harvey Nichols, the development was valued at over £125 million. A public square the size of Chamberlain Square was created to the front of the Mailbox beneath Suffolk Street Queensway. It was paved with natural stone and as well as being a social area, it was also designed to allow the easy movement of visitors to, from and around the building. The area to the rear of the building is used frequently by the public. At the back of the Mailbox a walkway leads over a bridge and to the canal towpaths near Gas Street Basin. A mixed-use building called the Cube, designed by Birmingham born architect Ken Shuttleworth's practice Make Architects with Buro Happold engineers forms the final phase of the Mailbox development and houses a rooftop restaurant, boutique hotel and residential flats. In 2004, BBC Birmingham moved into a new complex of studios at the Mailbox that replaced the previous Pebble Mill site in Edgbaston. The general public