Two of the UK鈥檚 largest construction companies were at the centre of takeover speculation this week as market rumours suggested Amec had followed Mowlem in becoming the latest firm to receive a bid.

It is understood that an approach has been made to Amec by an unknown bidder valuing the company at more than 拢1.2bn. The move comes as speculation increased over the potential sale of Mowlem to Carillion.

Market sources have suggested Spanish group Acconia could be behind the Amec bid. Amec has recently been shortlisted for the 拢1.7bn Olympic programme management contract, and has stepped up its interest in the nuclear clean-up market.

Amec declined to comment on the rumours.

Meanwhile, sources suggested that a decision was 鈥渋mminent鈥� on Carillion鈥檚 takeover of Mowlem. Carillion announced three weeks ago that it was involved in early-stage talks over a bid, and despite rumours of European interest, is regarded as the firm most likely to buy Mowlem.

Vivian and a group of directors are not involving others at all

Source close to Mowlem

A source close to Mowlem said the takeover had unsettled staff at the firm, who are unhappy that it is being handled only by Simon Vivian the chief executive, Paul Mainwaring, the finance director, and Arthur Moore, the development director.

The source said: 鈥淰ivian and a small group of directors are keeping their cards very close to their chests, and are not involving other senior people at all.鈥�

The source said many Mowlem employees were concerned about what would happen to their pensions in the event of a Carillion takeover. Carillion is thought to have been examining all Mowlem鈥檚 schemes and accounts, in particular its pensions deficit.