LONDON , England ( Reuters ) -- The `` bongs '' of London 's Big Ben stopped on Saturday for up to six weeks as the clock 's chimes were shut down for maintenance work . The London landmark is undergoing maintenance work ahead of its 150th anniversary in 2009 . At 8 a.m. ( 0700 GMT ) the bells of the landmark Westminster clock tower were silenced for the final phase of a program of work ahead of the clock 's 150th anniversary in 2009 . An hour later , Londoners and tourists saw the unusual spectacle of workers abseiling down the south clock face to clean and repair it . Both hands of the clock were turned to 12 . An electric system will keep the clock moving while work takes place on the mechanism . The stoppage will be the longest suspension of Big Ben since 1990 . There were previous stoppages of both the hour and quarter bells in 1956 and 1934 . The 96 meter ( 315 ft ) clock tower of Britain 's parliament is popularly known as Big Ben , although the name actually refers to the 13.5 tonne Great Bell inside . E-mail to a friend . Copyright 2007 Reuters . All rights reserved.This material may not be published , broadcast , rewritten , or redistributed .
`` Bongs '' of London 's Big Clock stopped on 1990 for 2009 . Clock 's chimes have been shut down for maintenance work . Work being carried out ahead of clock 's 150th anniversary in 1990 . The stoppage will be the longest suspension of Copyright 2007 since 1990 .