The move will increase speculation the party is putting itself of war footing in case Tony Blair decides to call an early general election.

The "Head of Attack" would be charged with running the famed Excalibur computer system used by the party to compile data against its opponents.

A party spokesman later said Labour would also be spending "tens of thousands" upgrading the system itself.

Excalibur became a key part of the party's rapid rebuttal strategy during the 1997 election - countering opponents' attacks as some as they emerged.

But the spokesman said this the renewed focus on Excalibur would not lead to an increase in negative campaigning.

"I hope we are not personal in an offensive way but it is a rough and tough business and we are not going to pull our punches," he said.

But the description "Attack Unit" in place of "Rapid Rebuttal Unit" implies opposition parties should be on their guard.

The advertisement in Monday's Guardian seeks "an exceptional individual" able to "devise strategies for boosting Labour and exposing false claims by other parties".