London Mayor Sadiq Khan is to take over control of the London Stadium, it has been announced.
An independent review was published on Friday morning, which said there had been 'a catalogue of errors' leading to massively increased costs after the conversion from the London 2012 Olympics to West Ham's home ground.
It was a 'bungled decision that has left the taxpayer to foot an annual loss of around £20 million', the review said.
Sadiq Khan lamented a the errors of decision-making in transforming London Stadium
The Hammers pay £2.5m a year in rent to use London Stadium for home fixtures
Mr Khan said: 'I ordered the review into the finances of the London Stadium to understand how key decisions were made about its transformation and why costs were allowed to spiral out of control.
'What has been presented is simply staggering. Not for the first time, it reveals a bungled decision-making process that has the previous Mayor's fingerprints all over it.'
Mr Khan ordered the investigation after it had been revealed that the bill to taxpayers for converting the centrepiece of the London 2012 Olympic and Paralympic Games into a multi-purpose venue had climbed to £323million.
London Legacy Development Corporation (LLDC), the body which operates the stadium for the Greater London Authority, admitted problems with the venue's retractable seating were the biggest cause of the rise in costs.
Premier League side West Ham, who have a 99-year lease on the 60,000-seat stadium, made a one-off contribution of £15million to the conversion costs and pay £2.5million a year in rent. The total price tag for the stadium, which also has a new roof, is estimated to be £752million.
Mr Khan commissioned a review by forensic accountants