tower. A group of four tower blocks located behind The Rep Theatre on Broad Street have also undergone an extensive renovation to improve their insulation and appearance. The largest high-rise housing estate in Britain was constructed at Castle Vale with 34 tower blocks on the site of Castle Bromwich Aerodrome. This became an unpopular area as it began to suffer from social deprivation and crime whilst the buildings were poorly constructed leading to maintenance issues. To tackle the downward spiral of the estate, one of the largest tower block demolition and renovation programmes anywhere in Europe began in Castle Vale, with the construction of new buildings, squares and green public open spaces. John Madin and Brutalism John Madin and his architecture firm made an impact on the city, from the 1960s through to the late-1970s, comparable to that of Martin & Chamberlain in the 19th century. His best known buildings included Birmingham Central Library, an inverted concrete ziggarat in the brutalist style, in Chamberlain Square. Built in 1974, it was once described as "looking more like a place for burning books, than keeping them" by Prince Charles. Madin's work was not highly regarded by the early-21st century political leadership within Birmingham. Clive Dutton, the city's former Director of Planning and Regeneration, described Madin's Central Library as a “concrete monstrosity”. There have been campaigns launched to get the building listed status in more recent times. However these have been unsuccessful and the building is being demolished. The Post and Mail building was completed in the late 1960s and upon its completion, the tower was hailed as a great achievement by the likes of Douglas Hickman, who worked with John Madin. A lesser known building in the city by John Madin, Metropolitan House, shows the variety of architecture he brought to the city. Metropolitan House exhibited the use of exterior materials other than concrete. However, as Modernist architecture fell out of favour in the 1980s, proposals for the redevelopment of many of the buildings constructed in Birmingham from the 1960s and 1970s were aired including redevelopment proposals for the Post and Mail Tower (most including the total demolition of the tower). In 2005, demolition work began on the tower and a replacement office block has been constructed in its place. A building of similar architecture, the Birmingham Chamber of Commerce on the Hagley Road, still remains, however is under threat from demolition