This article has been amended – see final paragraph for further details.
The Directory of Social Change has said it is "ironic" that charities are renting space overlooking London's Olympic Park while the government has yet to refund money diverted from the voluntary sector to pay for the construction of the site.
The DSC has had a long-running campaign to persuade the government to give back the £425m it took from the Big Lottery Fund in 2007 to pay for the ballooning costs of the 2012 Olympics, including the construction of the Olympic Park.
It has used this weekend's sixth anniversary of the closing ceremony of the London games to repeat its concerns, as charities such as Cancer Research UK and the British Council prepare to move into developments that it says have been boosted by their proximity to the Olympic Park.
A DSC spokesman said: "It's a historic irony that money was taken from charities across the UK to develop the park, hasn't been paid back and now charities will be paying rent for offices right next to it."
Outrage over the money taken from the BLF prompted the Labour government of the time to pledge to repay the debt from the sale of Olympics assets – a pledge subsequently reaffirmed by successive coalition and Conservative governments.
These assets are now owned by the London Legacy Development Corporation, which is responsible for the redevelopment of the park itself, but not the developments in which the charities will be renting premises.
A parliamentary question posed last year by Steve Reed, the shadow minister for civil society, revealed that just £57.5m had been recouped from asset sales.
With initial revenues from asset sales going to the Greater London Authority, not the lottery distributors, the DSC claims it could take more than 30 years to get to the full £425m repaid.
The DSC's big lottery refund campaign, supported by 4,000 charities, calls for an immediate return of the lottery cash.
Jay Kennedy, director of policy and research at the DSC, said: "We’re 11 years on from the big lottery raid in 2007 and six years on from London 2012. Yet few assets have been sold as promised and government statements are vague at best about when this will happen.
"At the same time, the value of new grants committed by the BLF fell by almost £200m in 2017 because of a fall in National Lottery revenue from ticket sales.
"They need a big lottery refund now, not in another decade."
A DCMS spokeswoman said: "The government is committed to paying back the £425m contributed by the Big Lottery Fund to support the London 2012 Olympic and Paralympic Games.
"We've been clear that the Big Lottery Fund will start receiving funds from the early 2020s."
A British Council spokeswoman said: "The British Council is due to relocate to our new headquarters in 2020."
A CRUK spokeswoman said: "We don’t think this is one for CRUK to comment on."
This story originally stated that the development CRUK and the British Council were planning to move into was owned by LLDC and located on the Olympic park site. This was based on a statement from the DSC, which in turn drew on inaccurate information on the Queen Elizabeth Olympic Park website, run by LLDC, which stated that the International Quarter London development was "located right in the centre of the park". The website has since been corrected.