The Olympic Park Legacy Company’s ability to maximise the economic benefits from the Olympic Park and the 2012 Games has been challenged by the London Assembly.

In a report out this morning, the assembly raises concerns about the implications of transferring and Olympic Park to the legacy company and highlights “a great deal of uncertainty” around the arrangements for post-Games development in east London.

Called “The Finances of the Olympic Legacy”, the report welcomes the setting up of the legacy company, which is chaired by Baroness Margaret Ford. But now Mayor Boris Johnson proposes to replace it with a Mayoral Development Corporation, the report warns this must not lead to further drawn-out talks over debt and ownership of land.

The report also reveals that the land transfer to the legacy company, which was finalised last month, will leave the London Development Agency (LDA) with £387m of debt.

With the abolition of the LDA set for March 2012, the report questions how this will affect the repayment of the debt and the amount of future funding available for London’s economic development

As an elected body that holds the Mayor to account, the assembly is seeking a response to the report from Johnson by February 2011. The report follows last week’s publication by the legacy company of its masterplan for the site, which includes the development of 8,000 homes.

John Biggs, chair of the assembly’s budget and performance committee, said: “A huge amount of money has gone into creating the Olympic Park and this investment must result in an economic benefit for east London and the capital as a whole.”

Biggs added: “Everyone thinks responsibility for the legacy is cut and dried, but our investigation suggests there are still many unanswered questions which need to be addressed if London is to get the kind of legacy that was promised.”

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