Proceedings in the Welsh assembly have been stopped and government services across the country shut down today as thousands of civil servants strike over pay and job cuts.
More than 200,000 members of the Public and Commercial Services (PCS) union, working in more than 200 government departments and agencies, are expected to take part in today's industrial action.
This afternoon's plenary session at the Welsh assembly has been delayed until tomorrow as 23,000 Welsh staff go on strike, while driving exams are being cancelled, court sittings are being disrupted and job centres are being forced to shut.
PCS has warned up to half a million tax returns could be delayed thanks to strikes at HM Revenue and Customs, although the department said enquiry centres will be open to receive last-minute returns and help make emergency tax credit payments.
Picket lines have also been set up outside the British Library and the National Gallery in London. No museums will shut because of the strike, but most - including the Tate and Natural History Museum - are having to shut some galleries or floors.
The dispute focuses on the government's plans to cut 100,000 civil and public service jobs as part of the Gershon efficiency savings. PCS also objects to the use of outsourcing, and the use of expensive external consultants while staff pay is capped.
"Today's strike illustrates the depth of anger over the damage crude job cuts are having and the growing frustration over below inflation pay offers," said general secretary Mark Serwotka.
"Far from having gold plated terms and conditions thousands of civil servants earn just above the minimum wage and a quarter earn less than £15,430.
"If the government are to avoid the prospect of more strikes and disruption then they need to give assurances over jobs, services and privatisation as well as making serious headway in tackling pay inequalities and low pay in the civil service and related bodies."
However, Cabinet Office minister Pat McFadden said there was "absolutely no need for this strike", insisting the government "value civil servants highly".
"At a time when the government is increasing investment in public services no organisation, including the civil service, can be immune from the need for change, both to ensure value for money for the public and to adapt to new technology," he said.
"There is an established process through which unions can raise any issues of concern they have with these changes without going on strike. Departments will do what they can to minimise the effect on important public services."