A compulsive gambler who is suing bookmaker William Hill for his £2m losses has also been allowed to seek damages for personal injury.
Graham Calvert is suing William Hill for £2m
Greyhound trainer Graham Calvert, 28, from Houghton-le-Spring, near Sunderland, claims the company failed in their "duty of care".
He said he had not only lost money but also his wife, health and livelihood.
The bookmakers denies any wrongdoing and said it cannot be held legally liable for Mr Calvert's losses.
But he claims he was allowed to place bets after asking the company to close his account under a self-exclusion scheme.
A High Court judge ruled on Wednesday he can also seek further damages.
Anneliese Day, representing Mr Calvert, said her client had developed a medical disorder known as "problem gambling" and should have been protected by William Hill.
The decision could mean a substantial increase in any compensation if William Hill is found liable.
The firm was accused of manipulating his gambling disorder to gain as much revenue as possible.
It is alleged William Hill allowed Mr Calvert to open two new accounts and to make bets totalling around £3.5m between June and December 2006.
During this period he lost a total of £2.1m.
The case is expected to end by Friday, when judgment will be reserved to a later date.