Marketing and advertising giant WPP has launched the bid battle for Tempus, an agency that plans and organises how and where to run ad campaigns, with a 555p per share offer.

The counter bid - valuing the firm at �437m - was widely expected and rivals an agreed offer from France's Havas. The French company is prepared to pay 541p per share.

WPP, which already owns 22% of Tempus, made the bid as it released first half results, reporting a rise in pre-tax profit to �247.6m from �137.7m last time.

The Tempus board on Monday withdrew its recommendation to shareholders to accept the Havas bid after WPP's offer.

The haves and Havas nots

Havas, the world's fifth largest advertising agency, wants to build up its media buying business and its offer is already considered by analysts to be over the odds at �425m.

Without Tempus, Havas will lack the clout to compete with larger players in the media buying world as its customers look for global agencies.

Havas is thought to be mulling a renewed bid of about 570p.

Tempus shares closed at 582.5p on Friday, after rising during the week in anticipation of a bid battle.

Tempus is not a must buy for WPP, but it would consolidate its position as the world's leading media buyer with its two existing firms, Media Edge and Mindshare.

WPP will also make a handsome profit on its 22% stake, which it bought for an average of 200p per share, if it loses. It's Tempus shares will have more than doubled in value.