Fears that Olympic stadium could become white elephant

Owner may not be known by end of Games as legacy company seeks new 'interested parties'

It was among Mayor Boris Johnson's manifesto pledges, to ensure that the Olympic stadium's "future is set before the Games begin". Less than a fortnight after his re-election, that will now not be happening.

An announcement over the stadium's future had been expected on 21 May, with West Ham the favourite of four bids to take the stadium on a 99-year lease, but the London Legacy Development Corporation (LLDC), has opened the process for a third time, allowing a further eight weeeks for bids.

The Corporation has changed the terms under which a bid can be made, and invited the dozen parties who initially registered an interest in taking over the stadium, but who did not in the end submit a formal bid, to reconsider their decision. The LLDC's chief executive, Andrew Altman, admitted that the original terms, which remain confidential, "may have deterred interested parties from bidding".

The LLDC, known until recently as the Olympic Park Legacy Company, has been going over the lengthy bid documents submitted by West Ham, a consortium led by the University of East London and Essex County Cricket Club, and two unknown bidders since late March.

Formal negotiations have not begun, but the "clarifications", as the LLDC calls them, that have been made to the terms since the bids were submitted include "governing body approvals, technical improvements to the stadium and the opportunity to bid for the right to exploit the stadium naming rights." West Ham face a legal challenge from Barry Hearn, the Leyton Orient chairman, who insists it is against Football League rules for West Ham to move within one mile of another league club.

West Ham are understood to want extensive renovations to the ground, including retractable seating and modifications to the roof, which the LLDC would have to pay for. Any new tenant would now be allowed some say in naming rights, which would be crucial if West Ham wished to attract a wealthy investor.

The East London club won the right to buy the stadium in the previous bidding process, which was declared invalid on a legal technicality after an anonymous complaint to the EU – a situation the LLDC and West Ham would be desperately keen to avoid happening again. Last week, Mr Johnson appointed a Conservative councillor, Daniel Moylan, as the new chair of the London Legacy Development Corporation. He will take up his post next month, and is expected to review all possible new expenditure at the park. The delay is the latest setback in an increasingly epic saga.

A spokesperson for Mr Johnson said: "The Mayor believes it is important the tender process is fair to all and as competitive as possible. If that means being patient and allowing more time to get the best deal for London then that is the right course of action to take."

Mr Altman said the stadium would still reopen in 2014 as planned. "This is a significant public asset and a 99-year lease, and it is right that we take the time now to get the best possible outcome for the stadium," he said.

Ground for concern: Olympic stadium woes

6 July 2005 London wins Olympic Games, promising a 25,000-seat permanent home for athletics

July 2009 London Assembly warns the stadium does not have a strong legacy and may become a "white elephant"

March 2010 West Ham United Football Club and Newham Council announce their intention to bid for the stadium after the Games

October 2010 Tottenham Hotspur and the entertainment promoters AEG also submit a bid

February 2011 West Ham win the bid process, largely through their pledge to maintain the running track

October 2011 West Ham's bid collapses after an anonymous complaint to the EU over the illegality of Newham Council's £40m loan, which constitutes "state aid"

January 2012 A new bidding process opens. Sixteen groups register an interest, including West Ham; four materialise into bids

14 May 2012 The bidding process opens again, wiping out the promise that the stadium's long-term future will be confirmed before the Games