The fate of one of Britain's biggest pub companies will be sealed in the next six weeks as Mitchells & Butlers thrashes out final negotiations with potential private-equity investors.

Today, it upped the ante by saying that despite plunging beer sales it has kept revenues moving ahead in the first six months of its financial year and gained a hefty market share from rivals.

A deal could see private-equity investors take a minority stake of up to 29% in the group at a cost approaching £400 million.

M&B, which includes the Harvester, All Bar One and O'Neill's chains, is reported to be weighing up competing offers from Permira and a consortium of CVC and Blackstone.

They could buy shares from existing shareholders, including Robert Tchenguiz, who is sitting on major losses from his own pub investments, or sub-scribe for new shares or a mixture of both.

Punch Taverns withdrew a potential merger deal last March and M&B also took a £274 million hit earlier this year after a disastrous bet on interest rates went wrong.

Today the group, seen as the most immune to the smoking ban and the consumer downturn because of its women and family-friendly pubs, said first-half sales had edged ahead by just 0.6%. But that was better than analysts feared and outstripped trading updates from rivals like Marstons and JD Wetherspoon.

M&B said the biggest collapse had been in beer sales, where across the industry they fell by 9% in the period from October to February. The market will continue to move away from pubs into supermarkets and off-licences, it predicted, with on-trade beer sales likely to remain depressed.

Its drinks sales fell 1.4% in the past six months, but food sales countered that with growth of 4.8%.

M&B now serves more meals in the UK than McDonald's, running at 110 million per year. It said that its huge buying power had helped it keep food costs under control.

But it added that its productivity gains, particularly through extra training for its staff, its value-for-money food offers and increasing market share in drinks sales should ensure a "resilient operating performance for the year as whole".

M&B will reveal its full first-half figures on 20 May and that will be the day it should also unveil its private-equity deal if it can be done at an acceptable share price in the current financial climate.

M&B shares rose by 3¼p to 333½p today.