British Passport Office workers have began a five-week strike in the increasingly bitter civil service dispute over jobs, pay, pensions and conditions.
More than 1,000 members of the Public and Commercial Services union (PCS) at eight sites walked out in an escalation of the long-running row.
PCS general secretary, Mark Serwotka said on Monday
According to Serwotka, picket lines will be mounted outside the offices in Glasgow, Durham, Liverpool, Southport, Peterborough, London, Belfast and Newport in Wales.
The union said those taking action will be supported by a strike fund.
Serwotka had written to the government calling for urgent talks in a bid to resolve the dispute.
He had accused ministers of treating its own employees differently to others in the public sector after negotiations were held with unions representing health workers and teachers.
The union is stepping up strikes, with a nationwide walkout of more than 130,000 civil servants planned for April 28.
