Richard Desmond, the owner of the Daily Express, hailed a victory for his Health Lottery after Camelot, the National Lottery operator, failed in a bid to close it down.
The High Court rejected Camelot's call for a judicial review into the Gambling Commission's decision to let the Health Lottery carry on operating.
Camelot boss Dianne Thompson argued her rival had breached the rules meant to grant the National Lottery monopoly status by buying a regional network of lotteries and promoting them nationally.
But Mr Desmond, who also owns Channel 5 and a string of adults-only satellite television channels, said: "The court said the application failed on merit. The judgement handed down is a pretty hard judgement."
He branded Ms Thompson a "second-hand car salesman" for labelling his charity unlawful.
"I would like a personal apology from them and I would like them to worry more about the charities which actually is why they have got their licence. How would you feel if you were a charity and you thought you were getting money from an unlawful operation? "
Camelot, bought two years ago for £389m by the Ontario Teachers' Pension Plan, fears the decision could pave the way for a spate of new lotteries that would eat into its ticket sales and jackpots. It has claimed it is losing £1m a week in sales to Mr Desmond's venture, set up last autumn, which gives 20p in the pound to good causes compared to its own 28p.
However, a 12 per cent rise in ticket sales last year to a record £6.5bn shows that it is still in good shape.
Camelot raised £750m for this summer's Olympics from themed tickets as part of a £2.2bn overall contribution and has become a big backer of British movies such as The King's Speech and The Iron Lady.
The Health Lottery will generate up to £30m for good causes in its first year, on sales of £150m.
Mr Desmond, who has committed £50m to the venture, hopes to break even within five years.