A charity has become the latest victim of the deadlock at the heart of the Stormont Executive, after it failed to gain approval for fundraising open days near the former Maze prison site.
The Ulster Aviation Society (UAS) hoped to attract 8,000 people to see its collection of aircraft housed in old wartime hangars on Stormont-owned land close to the prison buildings, but its plan has been consumed by the bitter political row between the DUP and Sinn Fein over stalled proposals for a peace centre in the one-time paramilitary jail.
Sinn Fein has withheld approval for the two open day events this month, claiming its stance is linked to a DUP decision to block public visits to the prison.
But the DUP has, in turn, accused the republican party of playing politics with a charity.
Society chairman Ray Burrows said the cancellations were a "tremendous setback".
"The whole UAS committee are devastated and at a loss to understand why permission has been withheld this year," he said.
The proposal to develop a peace centre at the Maze site near Lisburn, which is owned by the Executive, was envisaged in the Sinn Fein and DUP agreed Programme for Government but it was dramatically torpedoed last year when the unionists withdrew their support.
First Minister and DUP leader Peter Robinson, who said he was responding to victims' concerns about the potential of a centre at the former prison being turned into a "terrorist shrine", controversially announced the move via a letter penned from the United States while on holiday.
The spat is one of a series that have marked a serious deterioration in relations between the main partners in government at Stormont.
The aviation charity, which has been based at the Maze for 10 years and stores 23 historic aircraft in the hangars, has now lost out after Sinn Fein refused to give approval for the open days.
The society, which recently spent £10,000 to buy a Spitfire, hoped to raise £15,000 from the events.
While Sinn Fein has heavily criticised the DUP for not engaging on the wider development plans for the Maze, its position on the open days is related to a more specific row over public access arrangements to the prison buildings at the present time.
The republican party has accused the DUP of blocking visits to the buildings, insisting an "a la carte" approach to events on the site was not acceptable.
But the DUP has claimed Sinn Fein had turned the society into a "political football".
Mr Burrows claimed the Executive had not even officially informed the society that approval had been withheld and had just refused to respond to numerous queries for months.
He said the decision was all the more hard to understand given the success of similar open day events held over previous years.
"Planning for this year's event started in October '13 and, it would be true to say, it was shaping up to be our biggest and best yet," he said.
"We held off taking this decision as long as possible, but there obviously comes a time when it is impossible to continue; sadly, we have reached that point in time.
"We very much hope that the public and all those who had arranged to participate, especially the other charities involved, will appreciate the society's position and we look forward to their continued and valued support in the future."
Sinn Fein's Caitriona Ruane said the society's open days could proceed if the DUP agreed to re-open access to the historic prison building.
"There was an agreement on the development and use of the entire site which would have opened up its enormous potential in terms of job creation and economic development," said the South Down Assembly member.
"This was reflected in the agreed Programme for Government and was backed by £18 million in European funding.
"This agreement was reached after months of discussion and negotiation and was a compromise position which would open up the protected historic buildings at the Long Kesh site.
"At the behest of negative voices within the DUP, Peter Robinson then reneged on this agreement, unilaterally stopping all progress and preventing access to the prison building for thousands of tourists and other visitors. That remains the DUP position.
"The DUP cannot cherry-pick the parts of an agreement which they support and block the elements they have difficulty with. That is not how negotiations work.
"Sinn Fein is willing today to agree that the UAS open day can proceed as requested if access to the prison buildings is reinstated. We can then come back to discuss the wider issues around the full development of the site."
But the DUP's Jeffrey Donaldson blamed Sinn Fein Deputy First Minister Martin McGuinness for the impasse.
"This year's event has been approved by the First Minister but blocked by the Deputy First Minister," said the Lagan Valley MP.
"It is childish and petty for Sinn Fein to damage the work of the Ulster Aviation Society because a small republican clique demand that certain buildings take priority over everything else on the site."
Mr Donaldson said the wider redevelopment of the site should not be stopped because of the disagreement over the peace centre.
"The potential for 5,000 jobs, economic development and the usage of the site by the Ulster Aviation Society are part of the regeneration of the site and should proceed," he said.
"Unfortunately, the Ulster Aviation Society are being victimised as Sinn Fein block their open day in an apparent attempt to use it as leverage for their narrow political agenda."