A LEADING shareholder in the Dorset-based defence giant Cobham plans to vote against a £4billion takeover.

Shareholders have until Monday to decide whether to accept the bid from a US private equity firm.

Sanderson Asset Management, the 11th largest shareholder of the company, has put its weight behind criticism from the founding family of Cobham.

Lady Nadine Cobham, whose late husband Michael ran the business, wrote to the company’s largest investors recently arguing that the offer significantly undervalued the firm after a recovery over the past two and a half years.

Lady Cobham, who owns a 1.5 per cent stake in the business, has written to defence secretary Ben Wallace and business secretary Andrea Leadsom calling on them to intervene in the buyout by Advent International.

Liberal Democrat business spokesman Chuka Umunna and former defence minister Tobias Ellwood are also among those who have raised concerns.

In a reply to Lady Cobham, Sanderson said it has told the company board about its plans to vote against the deal, becoming the first institutional investor to openly oppose the move.

Christian Paaskesen, senior portfolio manager for Sanderson, said: “We broadly agree with your assessment of the offer and are inclined to vote against it. We have privately communicated our position to the board along with our desire to see the current management team continue their good work in the event a better offer does not materialise.”

Investors have been hoping a rival bidder will emerge to drive up the value of the business, which has around 10,000 staff, including more than 1,000 in Wimborne and at Bournemouth Airport.

Advent International has support from Cobham’s management as well as shareholder Artemis Investment Management.

The offer needs support from three-quarters of investors.