Trade union leaders representing 15,000 workers at Jaguar and Land Rover were seeking urgent talks with the management yesterday over the future of the two car brands.

The move came as the parent company, Ford, confirmed that it had appointed investment bankers to advise it on the future of two of Britain's best known names. Concerns that Ford is seeking to sell Jaguar and Land Rover have led to calls for the government to intervene to safeguard their future.

Dave Osborne, car industry national secretary for the Unite union, said: "We have been pressing for assurances for the future from Jaguar/Land Rover and will redouble those demands now."

Ford, which lost $12.7bn (£6.3bn) last year, has been reviewing the future of several divisions. One is its Premier Automotive Group, which includes Jaguar, Land Rover, Volvo and, until March, Aston Martin, which was sold to a consortium backed by Middle Eastern investors.

This month there were reports, denied by Ford, that it was in talks with BMW over the future of Volvo and there has been persistent speculation that the two remaining British marques could be sold. Yesterday Ford said: "We are looking, with our financial advisers, to determine the best future for Jaguar/Land Rover."

Land Rover employs 8,300 workers, mainly at its Solihull and Gaydon facilities. Jaguar has a workforce of 7,300 concentrated at Castle Bromwich, Whitley and Halewood on Merseyside, where it shares production with Land Rover.

The close ties between the marques makes it more likely they would be sold together but industry sources say there is far more interest in Land Rover, which has had record sales of late, than in Jaguar.

Several car manufacturers have already said they are not interested in buying the brands, leading to speculation they could be sold to private equity interests.

The Labour MP John McDonnell said: "I am calling on the government to intervene to prevent this sale, which could result in huge job losses and the consequent impact on those local communities affected."