John Laing this week called a halt to talks with a mystery buyer that made a takeover approach two weeks ago.

The firm, which has equity stakes in numerous PFI projects, announced on Wednesday that it was no longer in talks with the buyer.

In a statement to the stock exchange, Laing said: “Having investigated the approach more thoroughly, Laing does not believe that it is in the company’s or the shareholders’ interests to prolong the current discussions. Laing announces today that it is no longer in talks with respect to the approach.”

However, sources at Laing said they had not ruled out a hostile approach from the unnamed firm or another company.

A source said: “Laing has had no other expressions of interest but obviously this approach has focused market attention on the value of the company. We wouldn’t expect a hostile approach from the party in question but you can’t really tell. There is nothing to stop it coming back.”

Laing will issue a trading update on 17 January before its preliminary results, scheduled for 13 March.

It is being advised by investment bank Greenhill & Co.