Giant outsourcer Interserve continued to look fragile today as its shares plunged to a new all-time low despite the announcement of a new restructuring operation.

The UK-based global construction, equipment and facilities management company which employs 75,000 people worldwide insisted the 'fundamentals of its business remain strong'.

But the crisis intensified as its shares lost more than 75% of their value while it struggled to negotiate its second rescue deal this year and observers raised fears of another Carillion-style collapse.

The debt-laden group said the plan would mean 'substantial' losses for shareholders as the banks that have lent Interserve more than £600m take control of the company in the deal which it hopes to complete early next year.

In a statement Interserve chief executive Debbie White said the Cabinet Office had expressed support for the recovery plan.

'The fundamentals of our business remain strong,' she said. 'The deleveraging plan will give Interserve a strong long-term capital structure and provide a solid foundation on which to build the future success of the group.'

Interserve lists local government as one of its major areas of operation along with a wide range of sectors including aviation, defence, health and social care, oil and gas, transport and nuclear.

It says: 'We are an intelligent and strategic partner with deep experience of supporting local government. We work closely with councils to tackle problems, transform communities and change lives.'

At the weekend the Labour Party called for a temporary ban on Interserve bidding for any public contracts.

Shadow Cabinet Office minister Jon Trickett said: 'The Government must take urgent steps to ensure all existing contracts with Interserve are reviewed and that they are prevented from bidding for public sector contracts until they have proved they are financially stable and there is no risk to the taxpayer.'