Fujitsu employs about 12,500 people across the UK
Workers at Japanese electronics firm Fujitsu in the UK are staging the first of a series of one-day strikes in a row over pay, jobs and pensions.
Members of the Unite union are protesting about recent job cuts, pay freezes and the closing of a final salary pension scheme.
The union urged the firm to make "a sensible offer acceptable to members".
Fujitsu said it was "disappointed" with the strike action as consultations on pensions were continuing.
The firm "has taken prudent measures to ensure that service to its customers is maintained", it added.
Fujitsu has cut 1,000 jobs in the UK since August this year.
It now employs a total of 11,500 people in the UK, 1,500 of which are members of Unite, the company said.
Unite first warned of strikes in August and its members voted to take action last month.
"It seems that the company are hiding behind the recession to attack the pay and conditions of their workforce," said Unite national officer Peter Skyte.
"Our members would prefer not to strike, but feel strongly that Fujitsu is not listening to their genuine concerns and that enough is enough."
The company has 26 information technology services offices in England, Wales and Scotland.
Those in England are in Basingstoke, Birmingham, Blackpool, Bolton, Bracknell, Bristol, Crewe, Exeter, London, Lytham St Annes, Manchester, Newcastle upon Tyne, Slough, Solihull, Staines, Stevenage, Wakefield, Warrington, Warwick and Winnersh.
In Wales there are offices in Cardiff and Swansea and in Scotland in Dundee, Glasgow, Edinburgh and Inverness.
In Northern Ireland, the company also has premises in Belfast and Londonderry.