“In April our members agreed to changes to terms and conditions of their employment in order to give the company financial security, but like Oliver Twist, they are coming back for more.

“It appears that the company is making our members pay for their failure to secure Government funding.

“Unite’s members will not be paying for management’s incompetence and we will not stand by while those responsible continue to wreak havoc on this business.”

Bert Hill, regional officer of the GMB union, said: “GMB will be opposing everything we have heard so far. We will fight the company on this – of that I have no doubt.”

The union attacks came as JLR chief executive David Smith moved to defend the cutbacks programme, pledging the effect on jobs would be minimal.

Amid claims from some sources that 3,000 jobs were at risk under the new business plan, Mr Smith said: “This is a plan to provide employment for everyone who works for us, but there will always be a little bit of natural change in the number of employees.

“The point is to invest in new products, then have a fundamental growth strategy in terms of both the model portfolio and volumes.

“I am very confident about the employment side.” He confirmed that the new plans did not budget for changes in staffing levels.

Business Secretary Lord Mandelson backed the proposals, saying: “I know trading conditions are difficult for the car industry as a whole. It is inevitable that we will see further restructuring across the industry.

“I welcome the fact that JLR has already implemented a number of proposals to improve its long-term prospects.”