London Olympic Stadium taken over by mayor Sadiq Khan
London Mayor Sadiq Khan has agreed to take over the former Olympic Stadium amid "financial challenges".
Mr Khan says a "catalogue of errors" by his predecessor Boris Johnson led to the costs of transforming it into West Ham United's new ground soaring.
An independent review says the conversion cost £323m - the original estimate was £190m.
Mayor of Newham Sir Robin Wales said Mr Johnson left the stadium's finances in a "dreadful mess".
The review says that E20, the public sector company set up to run the London Stadium, is projected to make a loss of £20m next year and a total loss of £140m over its first 10 years.
Mr Khan claims Mr Johnson's decision to make taxpayers foot the bill means Londoners will have to shoulder the predicted loss.
He will take control of the stadium in order to "renegotiate deals" and "minimise ongoing losses".
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."
West Ham were awarded tenancy of the stadium in 2013, however under the agreement the club would not have to pay for certain running costs.
These instead would be paid for by the taxpayer and include policing, stewarding, goalposts, corner flags, cleaners and turnstile operators.
However, the review notes that since that deal was signed, policing and stewarding costs have "increased notably".
West Ham said: "The concession agreement is a watertight, legally binding contract signed in 2013 in good faith by West Ham United, who remain absolutely committed to its terms for the entire 99-year duration.
"It is not in West Ham United's interests for the stadium to be not performing in line with aspiration and, as we have done ever since moving to Stratford in the summer of 2016, we continue to offer the benefit of our commercial expertise and substantial experience in managing successful stadia."
The club added the stadium "craves renewed leadership" and it welcomed "the mayor's decision to step in and deliver this".
Newham Council said it received a business plan from E20 in October 2016 which indicated there was likely to be an "ongoing deficit" which could make it "financially unsustainable" in the long term.
An internal review was carried out by the council at the same time the Mayor of London launched his own inquiry.
Reacting to Mr Khan's takeover, Sir Robin said: "On behalf of Newham residents, I am angry that the deals and decisions made by the former Mayor of London and his administration have left the stadium finances in such a dreadful mess.
"It is regrettable that the finances of the stadium have not followed the expected course."
He added it was "vital" for Newham that the stadium remained a public asset.
A source close to Mr Johnson, who was the Mayor of London between May 2008 and May 2016, rejected the criticisms.
He said: "No other city has an Olympic legacy like London's - all seven venues on the park are in private hands, with millions of visitors a year, and a positive economic legacy for east London.
"The stadium has a secure future with athletics and football.
"The mistakes belonged to Khan's Labour predecessor Ken Livingstone and the Blair government. Signing off on a stadium fit only for athletics was a massive error. The only option for Boris was conversion to a multi-use venue."