Troubled support services group Amey, which has its headquarters at Sutton Courtenay, near Abingdon, has been targeted by a so-called "value investor".

Amey is facing calls to break itself up or sell up after Meditor Capital Management, which invests in risky companies on behalf of clients, increased its holding.

Meditor now owns 14.69 per cent of Amey after increasing its stake from three per cent following the sharp fall in the group's shares this week.

Many of its clients are hedge funds -- volatile, open-end investment companies which offer investors large gains, but with high risks.

Amey shares have fallen 58 per cent since the resignation of its new finance director Michael Kayser last Wed- nesday. This week they have fallen by 4p to 25p.

Amey shareholders have called crisis meetings over Brian Staples's position as chief executive.

Chairman Sir Ian Robinson said "two or three" shareholders had expressed concern about Mr Staples' leadership of the company. However, he said he had the "full support" of the board.