The collapse of the King City casino resort project in Hungary is threatening to drag politicians - including former Prime Minister Ferenc Gyurcsany - and investors into a bitter dispute.

Led by Cyprus-based developer Vigotop, King’s City was to be a $1bn multi-purpose entertainment complex featuring a large-scale casino in Sukoro, near Lake Velence.

However, despite winning the contract to develop the property, KC Bidding, a joint venture between Vigotop and Trans World Corp, was told by the government in January that this agreement had been terminated for failing to provide progress reports.

KCB and the government are now involved in a legal dispute through the Hungarian courts, with each claiming the other is guilty of breach of contract.

KCB has also submitted a claim to the International Centre for Settlement of Investment Disputes, part of the World Bank.

Now, allegations of corruption have been leveled against Gyurcsany over the legality of the project. The authorities are understood to be in favour of lifting his parliamentary immunity in order to pursue the investigation.