German telecoms group Mannesmann, which is the target of a hostile €131 billion bid by Britain's Vodafone AirTouch group, begins a UK-based advertising "charm offensive" next week.

The campaign, due to start next Monday, represents an escalation in the battle for the hearts and minds of shareholders initiated by Vodafone in Germany last week as both sides square up in the world's biggest corporate take-over battle.

This has already seen German newspapers carry a Vodafone advertisement showing a mother breast-feeding a baby. The caption on the advertisement reads: "If you want to grow up, you need a good mother."

This was a response to Mannesmann's prominent publicity, featuring a picture of a baby, hands exposed, with hospital-style wristbands showing the names of the group's various European telecommunications brands.

Yesterday's message, printed boldly across the picture, stated: "an unfriendly mother would be the worst of all", with a toll-free number displayed prominently across the top for readers seeking further information.

Such high-profile publicity - matched by full and double-page Vodafone spreads - is highly unusual in Germany. According to one estimate, the combined campaign, allowing for bulk discounts, is costing about 300,000 deutschmarks a day.

Mannesmann said its German defence would continue along similar lines next month, with changes to the text as required. But it declined to give any details of its planned British advertising strategy.

Telefonica, the Spanish telecoms group, said yesterday that vice-chairman Mr Javier Revuelta was leaving the company. "Javier Revuelta del Peral, vice-chairman of Telefonica, has decided to take a different turn in his professional career and is leaving voluntarily his duties in the Telefonica group," the company said.

Meanwhile, Vodafone is increasingly seen as the front runner in its take-over battle with British Telecommunications for control of Airtel, the Spanish mobile phone company, even though it has submitted a lower bid, analysts said yesterday.

The competing bids are this week being considered by BSCH, Spain's financial services group, which controls 30.45 per cent of Airtel and has a syndication agreement with four regional savings banks that own a further 13.13 per cent of the mobile operator.

BT is understood to have valued Airtel at £26.4 billion sterling, against a reported £24 billion valuation by Vodafone AirTouch. Both bids involve all-share transactions and would gain BSCH about 5 per cent of either UK operator.

Ibersecurities, a securities company, said Vodafone AirTouch, as a pure mobile company, appeared to be the more attractive bidder.