Plans to announce the site of Britain’s first super-casino next week look set to be mired in legal action, it emerged yesterday.

Backers of the two front-runners to host the Las Vegas-style centre – Blackpool and Greenwich – raised the threat of court action yesterday if they were unsuccessful.

The location of the super-casino will finally be unveiled on Tuesday, along with the venues for eight medium-sized and eight smaller casinos.

The bid from Greenwich council, in south-east London, involves putting the casino in the Millennium Dome.

But five other local authorities – Cardiff, Glasgow, Manchester, Newcastle and Sheffield – also competing to host the giant venue of at least 5,000 sq metres and with up to 1,250 „Category A“ unlimited jackpot gaming machines.

After Tuesday’s announcement by the Casino Advisory Panel in a 180-page report, the decisions will then have to be approved in a vote by MPs and peers.

Losers in the race for the Las Vegas-scale casino may well get the consolation prize of one of the medium-sized venues which will be at least 1,500 sq m and have up to 150 „Category B“ gaming machines with a maximum GBP 4,000 jackpot.

But the super-casino assessment process, which began in September 2005, has been dogged by allegations of potential ministerial favouritism for Greenwich.

In particular, John Prescott, the Deputy Prime Minister, has faced a host of questions over close links with Philip Anshutz, the American tycoon whose Anschutz Entertainment Group (AEG) is behind the Dome casino project.

And yesterday, Blackpool council warned that it might go to court if it lost out.

The Lancastrian resort is banking on a super-casino to pull in vital private investment to help fund a GBP 2.5 billion revival of the town.

A Blackpool council spokesman said: „If it’s a ’no‘, we will not know until the day. That is when we will make a decision on what the next step forward will be.“ But she added that legal action „is not ruled out“.

There was speculation yesterday that other bidders were also considering a legal challenge if Greenwich emerged as the winner.

However, AEG, which overall is pumping GBP 350 million into the Dome, is also now raising the prospect of mounting a formal challenge if the decision goes against Greenwich.

David Campbell, the chief executive of AEG in Europe, said: „Legal action is definitely a possibility. If we felt there were grounds, then we would do it.“

Separately, Mr Campbell told The Daily Telegraph last week that he was „pretty confident“ about the outcome but admitted there was „no plan B“ for the Dome site.

He added that the panel would „award it on its merits. I think Greenwich has got a very strong case“.

Last night, the Casino Advisory Panel – which is chaired by planning expert Prof Stephen Crow and was appointed by Culture Minister Dick Caborn – insisted that the assessment process had been fair.

„It’s a very full report that sets out all the evidence to back up what we have decided,“ she said.

She also scotched rumours that the panel would try to avoid a huge row over its recommendations by saying that it could not choose between the top bids for the super-casino. „We were asked to come up with one choice and that’s what we are going to recommend,“ she said.

A spokesman for the Department for Culture, Media and Sport (DCMS) also dismissed the idea of legal challenges.

The assessment of where the giant casino should be built had been „an independent process“, he said.

Tuesday’s announcement will be followed by a statement in the Commons from Tessa Jowell, the Culture Secretary. She is likely to set out how MPs will vote on the casino proposals.

The DCMS spokesman stressed that the final decision on the location of the huge casino and the smaller venues would rest with Parliament. „There has to be an affirmative order in both the Commons and the Lords,“ he said.