British Telecommunications (BT) will cut 55,000 jobs by the end of the decade in an attempt to cut costs.
Customer services roles will account for up to a fifth of all redundancies.
Departing customer services staff will be replaced by technologies, including artificial intelligence.
However, the overall cut backs will include both staff and contractors.
Fibre broadband engineers from Openreach, the infrastructure arm of BT work on a fibre cable junction in central London
BT, which is the UK’s largest broadcast and mobile provider, currently employs a total workforce of approximately 130,000.
The company’s chief executive Philip Jansen said: “Whenever you get new technologies you can get big changes.”
Jansen, 56, who took over at BT's boss in 2019, claimed AI would make services faster and more seamless.
He added: “We are multi-channel, we are online, we have 450 stores and that's not changing at all.
A BT logo on a van in London
“There are plenty of opportunities for our customers to deal with people at BT, plenty of people to speak to.”
BT’s announcement comes as the company continues to move away from copper to its fibre network.
The decision to axe between 40,000 and 55,000 jobs by 2030 is likely to disproportionately impact UK-based staff.
Around 80,000 employees are located in the UK and around 20,000 staff are abroad.
A general view of the BT headquarters in Brentwood, Essex
The cut backs will include more than 15,000 people working on BT’s fibre networks, little over 10,000 as UK networks require less maintenance, more than 10,000 from using alternative technology and around 5,000 from restructuring.
BT reported a 12 per cent drop in profits of £1.7billion for the year to April.
Shares also dropped by more than seven per cent.
Shares fell 1.5 per cent to 148.10p on Wednesday but stock is up 32 per cent so far this year.