An attempt to block the government's plans for a new super-casino has been launched at the High Court in London.
Manchester has been earmarked to house the UK's first super-casino
The British Casino Association argues that operators of the development, along with those of 16 other new casinos, will have an unfair advantage.
Michael Beloff QC, for BCA, told the court Culture Secretary Tessa Jowell had displayed "blatant unfairness".
Ms Jowell's lawyers said the challenge was "without merit". Manchester was the preferred site for the super-casino.
Peers rejected plans for 17 casinos, including the super-casino, in March, but the government says it intends to continue pressing forward with its policy.
The application for judicial review is being held before Mr Justice Langstaff.
The three-day hearing will seek to establish whether the Gambling Act discriminates against them.
The BCA represents the interests of existing casinos, and its legal action is being backed by five of its member companies which operate 116 of Britain's 138 casinos.
Mr Beloff told the court lost profits could be as much as £120m a year.
And he said the culture secretary had not lived up to her "duties of fair consultation".
But Ms Jowell's lawyers said the case should be dismissed.