Luminar, the bar, restaurant and nightclub operator, is seen as the front-runner to buy Yates Group after the Wine Lodge operator issued a statement Friday lunchtime revealing it was "in preliminary discussions regarding a possible offer".

Yates was obliged to issue the statement to the Stock Exchange after the company's share price rose by more than 20% on Friday morning.

Other possible bidders which have been mentioned include Regent Inns, SFI, Georgica, Robert Breare's Noble House, JD Wetherspoon, a clutch of venture-capital houses and even Yates's own chairman, Peter Dickson, great-grandson of the man who founded the company in 1884.

Yates, which has 126 outlets, said that "a further announcement will be made as soon as possible."

By the end of business on Friday more than 667,000 shares in the group had changed hands, with the price rising 40p on the day to 219.5p. The new price means the group has a market cap of more than £142m, a rise of more than two thirds since December 19 last year, but still less than the £166.2m Yates was capitalised at in August last year before it issued a profits warning. The company's share price plunged 21% on the day of the warning, to 179p, an it was tipped as a possible takeover target at the time.

The logic behind a bid by Luminar is that acquiring Yates would give the group an extra edge in the forthcoming battle for the late night market. Even before licensing laws are liberalised, as planned, around half of Yates's outlets have licences to 1am or later, and many are said to be well-positioned to act as feeder bars to Luminar's own late-night venues. Yates also has a site pipeline that could be useful.

However, at the time of Luminar's full-year results early last month, the company's chief executive, Steve Thomas, specifically declared that another big acquisition like the purchase of Northern Leisure last year was not being contemplated, saying: "We're not looking at any large deals at the moment."

Luminar, now part of the FTSE 250 index of medium sized companies, was founded in 1988 and floated in 1996. It has seen its shares rise by more than 40% since the beginning of the year.

Yates's annual results are due to be announced this Thursday, June 14, when a statement on a bidder is likely to be made. Analysts are expecting the company to announce a fall in profits of 13% to £13.6m. The company recently started a refurbishment of all its 113 Wine Lodges at a cost of £150,000 an outlet. To justify the money it needs to be seeing an increase in sales of 8%, but it believed to be getting only 5%. The company also runs Ha! Ha! bars and Addisons.