Public accounts committee reveals that annual maintenance cost of Hyde Park memorial has doubled to £250,000.
The public accounts committee has criticised "basic project management failures" for the escalating costs of the memorial fountain for Diana, Princess of Wales.
The committee's report on the finances of the Royal Parks Agency, which runs London's eight royal parks, today revealed that its annual maintenance cost for the fountain has doubled to £250,000.
The initial spend on the fountain was £5.2m, well over the £3m budgeted by the government.
The report said: "The problems with the fountain reflected basic project management failures.
"The fountain was a small-scale project, yet there were multiple stakeholders whose roles, responsibilities and accountability for the finished result were not clear.
"Nor were there clear plans for managing the project risks."
The fountain had suffered delays before its opening by the Queen in 2004 because of disagreements on its design and it has since been closed because of flooding and then safety issues.
The chairman of the public accounts committee, Edward Leigh MP, said: "There are lessons aplenty here for the proposed project to erect a memorial to Queen Elizabeth, the Queen Mother."