Although all 762 apartments at Pan Peninsula in Seán Mulryan's 48-storey development were sold off the plans at the peak of property boom, with some buyers paying deposits of up to €2.6m, many are now struggling to pay the remainder, which is due upon their apartments' completion.

The situation has become so desperate that the buyers have taken the unusual step of forming an action group, the Pan Peninsula Buyers' Association (PPBA), in a bid to broker a compromise with Mulryan's company, Ballymore Properties.

This group claims that up to 50% of buyers are now unable to pay what they owe to Ballymore – a figure which is strongly disputed by the developer, which says that only 10% of buyers are in financial difficulty.

The emergence of the PPBA is a source of huge embarrassment for Ballymore, which had consistently brushed away fears that Pan Peninsula could be badly hit by the global credit crunch.

In September 2007, the development's sales manager David Lairn Hibberd admitted to the London Times that most buyers had been "wealthy, high-flying Canary Wharf executives who mostly use it as a second home".

But Lairn Hibberd said that despite this fact, the emerging banking crisis would have little impact on the development's success.

"If banks lay off staff, they take more on a few months later. Anyone rich enough to afford one of these flats is very good at their job and unlikely to be unemployed for long. They might buy one flat instead of three," he said.

Eighteen months later, however, many Pan Peninsula buyers are facing long periods of unemployment while those who remain in employment are struggling to secure sufficient finance to pay for their properties.

Many early purchasers have also seen their banks reduce their original pre-credit crunch mortgage offers, leaving the buyers to make up the shortfall themselves.

"When these properties were originally purchased, there were lots of mortgages around, even at 95% of the property's value," said Denesh Bhabuta, a PPBA committee member, who spoke to the Sunday Tribune. "But with the economic downturn, there are fewer products out there and the maximum lenders are now willing to give is between 60% and 70% of a property's value."

The situation has been compounded by a drop in the value of apartments at Pan Peninsula – which had originally sold for between €278,000 and €13m – of between 15% and 35% in recent months.

This means that those who can afford to pay Ballymore are already facing negative equity.

Ballymore had refused to engage with the PPBA, which represents over 300 buyers, and has sent legal letters to some of its members seeking immediate payment.

It has told buyers that they are "required to proceed with the purchase at the contract price" because contracts were not "exchanged on a subject-to-mortgage basis".

"Contractually speaking, Ballymore are perfectly allowed to do this but they should take account of the general business environment and the large number of units involved," said Bhabuta.

One difficulty facing any talks between Ballymore and its buyers is the fact that the PPBA is split regarding what it wants the talks to achieve.

Those who bought apartments as investment properties don't want Ballymore to reduce the value of their apartments while many of those who intend living there do. "In one way, people want Ballymore to reduce their prices to aid completions but on the other hand, they don't want their property's value to fall," said Bhabuta.

Meanwhile, some buyers are engaging in desperate measures in an attempt to make up the shortfall and there have even been rumours that some unemployed bankers have tried to max out their credit cards to pay for their apartments.

When contacted by the Sunday Tribune, Ballymore said it was willing to discuss cases on an individual basis but wouldn't comment further.

However, its communications director Paul Keogh has given a series of interviews with British newspapers indicating that Ballymore has had to establish a special department to deal with Pan Peninsula buyers in trouble. "There are less than 10% of purchasers finding difficulty [securing the] finance to complete – we have set up a special department to help them," he has said.

Keogh has also warned buyers against talking to the press about their difficulties, saying that "it may be counterproductive to be constantly going to the media about Pan Peninsula as it creates a negative hue around what is undoubtedly the best place in London to live at the moment."

Ballymore's desire to avoid publicity regarding Pan Peninsula is a far cry from its high-profile sales campaign, which saw Mulryan commission a yacht to ferry prospective buyers to a floating marketing suite. It seems likely, however, that the development will attract headlines for the foreseeable future, particularly as the PPBA is now seeking legal advice on how its members can withdraw from their original sales contracts.

Anglo Irish Bank Involved In Sale of Pan Peninsula Apartments

The Pan Peninsula buyers worst affected by the credit crunch were later purchasers, many of whom bought their apartments from Bantra, an Irish investment vehicle.

Bantra bought 238 apartments from Ballymore before reselling them for a higher price. The company itself was sold to Ballymore in March 2008 and the identities of the investors behind it remain unknown.

All Bantra's shares were held by a nominee company controlled by Anglo Irish Bank while the firm's two original directors were Anglo employees.

The Pan Peninsula Buyers Association has claimed that Bantra was a joint venture between Ballymore and Anglo Irish but sources close to the bank said the vehicle had nothing to do with it.