One of the United Kingdom's largest companies is cutting 13,000 jobs in a bid to save billions.

Media group BT (BT) announced the job cuts on Thursday, saying they will be made over three years and affect mainly back office and middle management roles. Two-thirds of the job cuts will be in the United Kingdom.

The company, formerly known as British Telecom, said it would hire 6,000 new workers as part of a broad restructuring of the group.

It will also quit its 10-story headquarters in central London.

Formerly the UK telecommunications monopoly, BT now competes with other companies to sell TV, broadband and phone services. It's also the owner of mobile operator EE.

The company said the overhaul, which will simplify a complicated management structure, will save it £1.5 billion ($2 billion) over three years. It will cost £800 million ($1.1 billion) to implement.

BT shares dropped 8% in London following the announcement.

CEO Gavin Patterson has sought to turn the page on an Italian accounting scandal that has harmed the company's profits.

"This position of strength will enable us to build on the disciplined delivery and risk reduction of the last financial year," he said in a statement.

BT also outlined a new pension plan on Thursday that it says will help close a funding deficit over 13 years. It will make payments of £2.1 billion ($2.9 billion) before 2020 and issue another £2 billion ($2.7 billion) in bonds.