Northern Rock shareholders are to reveal details today of their plans to take legal action over compensation.

The UK Shareholders Association, which has been advising Northern Rock shareholders, noted on its website yesterday that shareholders "will have to resort to legal action to establish their proper rights and to gain fair redress for the confiscation of their property".

The moves come as the head of the newly-nationalised mortgage lender is on a collision course with unions after the company announced plans to axe more than 2,000 jobs.

The group is set to cut a third of its workforce of just over 6,000 under proposals to halve the size of the firm and pay back around £25 billion in Bank of England loans racked up since its crisis last September.

Executive chairman Ron Sandler said any job losses were "extremely regrettable", but did not rule out compulsory redundancies.

Most of the cuts will come this year, striking a blow to the Newcastle-based lender's north-east heartlands.

Union leaders said the news would cause further uncertainty for the workforce and would oppose any compulsory redundancies.

Graham Goddard, deputy general secretary of Unite, said: "The employees have already faced months of insecurity and anxiety about their future.

"We will be working to mitigate the implications of the recent crisis on the employees who have worked tirelessly to ensure there is a sustainable business in the future."

But Mr Sandler said: "This is not just about shedding jobs, this is about preserving Northern Rock as a viable financial institution capable of being returned to the private sector."

As well as the job cuts, Northern Rock plans to shrink the size of its mortgage book to around half the current level of around £110 billion in a bid to create a smaller business, focused on low-risk mortgage lending and building up savings deposits.

It aims to pay off the Bank loans and free the Government from its guarantees over the business within three to four years before a return to the private sector.

The UK Shareholders Association on its website said MP Peter Atkinson had raised the complaint of one of his constituents who was 80 years old and was relying on their investment in Northern Rock shares "to help support the rest of my life".

It adds: "Like us he raised the question of why the valuer is being told to assume the company is unable to continue as a going concern and is in administration when clearly it is a going concern and not in administration."

And it says: "Valuations should be done based on the real circumstances and taking all the known factors into account, not on some artificially dictated criteria."