A major operator of bars and nightclubs has highlighted the uncertainty facing the industry ahead of a shake-up of the UK's licensing laws.

Even though extended hours are due to be introduced next week, Luminar said it was still hard to predict the impact of the overhaul.

It said it faced one of the biggest changes to the market place for years, but was confident it had "sound operational plans" to deal with the laws.

The firm, which runs Birmingham's The Jam House, said most of its clubs would stay open until 3am instead of their current 2am, while some will close at 4am.

Unveiling a five per cent rise in pretax profits to £19.9 million for the six months to September 1, Luminar said it remained "cautiously optimistic" about the rest of its financial year.

Chief executive Stephen Thomas said: "The impact of licensing reform remains unpredictable, but the company is operationally prepared to meet this challenge."

Traditional pub closing times will be consigned to history next week when the new laws are expected to come into force.

The comments came as Luminar reported a slight deterioration in recent trading, with like-for-like sales flat during the first half and 0.5 per cent lower in the nine weeks since then.

Luminar, which has 227 outlets, said it expected the market to remain highly competitive and for trading conditions to remain difficult.

Although turnover fell to £154.4 million in the period from £158.8 million last time, profits were driven higher by better buying strategies and more targeted drinks promotions.