Fujitsu has announced plans to cull up to 1,800 UK staff, over 15 per cent of its UK workforce.
The Japanese company said that the job losses are the result of a transformation programme designed to improve efficiency and enable the company to remain competitive.
The cost-cutting has become necessary as a result of increased cloud use by Fujitsu's traditional customer base as firms choose to consume as-a-service offerings rather than purchase and run their own infrastructure.
The firm will hope that by cutting costs it can afford to lower prices and become more competitive, but Unite has described the cuts as a "hammer blow" to the UK economy.
"This is a hammer blow for these hardworking employees who have given their all to make the UK subsidiary highly profitable," said Unite national officer for IT Ian Tonks.
"It is not good news for the UK economy as the company says that it intends to offshore many of these jobs, with increased automation also responsible for job losses.
"Fujitsu's main UK subsidiary made £85.6m profit last year and we see no reason for these job losses. Unite will do its utmost to fight for these jobs, as well as giving our members maximum support at this very worrying time."
Fujitsu has yet to announce which jobs will be lost, or from which of its sites. The firm has offices in London, Belfast, Bracknell, Crewe, Derry, Manchester, Stevenage, Wakefield and Warrington, among others.
It is thought that most of the cuts will take place next year, although some may be pushed into the following year.
Fujitsu said in a statement: "Fujitsu is planning a transformation programme that will enable it to better support customers in the era of digital transformation.
"The company today advised its employee representative forum of plans to restructure the organisation in order to provide better service and respond more quickly to customer needs.
"As part of the programme, Fujitsu plans to streamline operations in order to remain competitive in the market. Proposed measures include changes which would result in a reduction of up to 1,800 jobs in the UK.
"All affected employees will be offered guidance and support, and Fujitsu is establishing a consultation process with elected employee representatives."
Fujitsu president Tatsuya Tanaka warned before the referendum on EU membership that a Brexit would be a "huge negative" for the firm's UK-based IT business.
However, the firm claimed that this round of job cuts is unrelated to Britain's decision to leave the EU.
It was reported earlier this month that Lenovo is in talks to acquire Fujitsu's PC business.
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