The soaring value of smaller exploration and production companies to the larger oil majors struggling to increase their production was underlined yesterday when London-based Burren Energy revealed it had rejected a number of hostile bids valuing it at more than £1.5bn.

Closing market report: A billion pound bid, a deal between two major brewers, a host of takeover speculation and a U-turn over Northern Rock kept traders busy today ahead of the pre-budget report. By Nick Fletcher.