Uncertainty is hanging over hundreds of jobs in Sussex after BT announced it was cutting 10,000 posts.

The telecoms giant, which employs 1,800 people in Brighton, Crawley, Gatwick and Worthing, said it was shedding jobs as part of an “ongoing efficiency programme”.

Union leaders expressed shock at the scale of the cutback and warned they would resist any moves to make compulsory redundancies.

The company said it had already cut 4,000 jobs, leaving a further 6,000 to go between now and March, which will mainly affect BT’s indirect labour force such as agency workers, contractors and offshore staff.

Brighton Kemptown MP Des Turner said the situation was worrying for hundreds of BT workers in the county.

He said: “It is extremely unsettling and worrying for people working for BT in the city and in Sussex. “I fear this is somewhat premature by BT. I can’t imagine the business has been affected to this extent by the economic downturn.

“The threat of losing their jobs over the next year is not exactly going to raise staff morale.”

BT, which has a global workforce of 160,000, said it will achieve the reduction in its direct staff largely through natural turnover. Ian Livingston, BT’s chief executive, said 7,000 workers left the firm every year so he did not envisage any compulsory redundancies in the latest round of cuts.

But Andy Kerr, the deputy general secretary of the Communication Workers Union (CWU), said: “Ten thousand jobs is a huge number and it will be difficult for BT to shed that amount in one year.

“We’ll be holding BT to their statement that there will be no compulsion to meet these cuts.

“The CWU will oppose any compulsory redundancies by whatever means necessary.”

The job losses add to a week of gloom on the employment front, with more than 15,000 redundancies announced nationwide in recent days and official unemployment reaching an 11-year high.

A spokesman for BT said: “This programme is primarily about BT reducing its dependence on consultants and contractors.

“About 7,000 direct staff leave BT every year so this year it is really about us not replacing a large number of those people.

“Direct staff reductions will be achieved through voluntary schemes and us not replacing people who retire or leave the business.

“The jobs to go will be peppered around the world rather than concentrated in a few areas.”