Named after the popular video game in which little yellow characters gobble up attacking rival figures, the so-called Pac-Man defence is considered an extremely aggressive strategy that can be used only in very specific situations.
Despite the use of a Pac-Man defence in the hostile takeover fight between French oil companies Elf Aquitaine and TotalFina, merger experts do not expect it to gain popularity.
In a Pac-Man defence, a company that is the target of a hostile takeover seeks to defend itself by launching its own bid for the aggressor.
The Pac-Man defence was created during the ferocious takeover wars of the 1980s, a period in which corporate raiders launched attacks on some of the country's biggest companies.
The Pac-Man defence has become increasingly rare in the States since the 1980s, partly because companies launching hostile bids now make sure they have their own defensive measures in place before going on the attack.
Marston has launched a counter bid for W&D, using the so-called Pac-Man defence, where the takeover target turns the tables on the predator.
The City acknowledges the Pac-Man defence as a spirited rejoinder but there is little faith in it succeeding.
Letchet's radical bid for Wolverhampton & Dudley Breweries - which has already offered pounds 262 million for Marston's - has been dubbed a Pac-Man defence
, after the 80s computer game where both sides tried to gobble each up.