A wave of protest will sweep across Britain today as hundreds of thousands of public-sector workers – 30,000 in Scotland – go on strike in opposition to the UK Government's proposed changes to their pensions.

The Coalition insists the Public Service Reform Bill, one of 19 measures announced in its second Queen's Speech yesterday, will create a common framework across public-sector pension schemes, ensure millions of workers receive a "good pension on retirement" and make public-sector pensions affordable and sustainable with costs shared more fairly.

A Treasury spokesman explained: "Public service pensions will remain among the very best available. Most low and middle-income earners will receive pensions on retirement that are at least as good, if not better, than they would receive now, while those closest to retirement will be protected."

However, the unions insist the planned changes from 2015 will simply mean workers will have to work longer and pay more for less.

The protest will involve civil servants, health workers, Ministry of Defence staff, immigration officers, lecturers and members of the Royal Fleet Auxiliary.

UK and Scottish Government departments will face disruption as will courts, driving test centres, tax and benefit offices and Jobcentres.

Picket lines will be mounted outside Government buildings, including the Scottish Government's headquarters at St Andrew's House and the Scotland Office in Edinburgh, the Holyrood and Westminster parliaments, and Faslane Naval Base.

Glasgow Sheriff Court, tax offices and the Registers of Scotland in Edinburgh will also be picketed, along with the Department for Work and Pensions and the passport office in Glasgow.

Museums and art galleries will be affected while rallies will be held across the UK.

The Public and Commercial Services Union (PCS) will hold a rally, to be addressed by its national president, Janice Godrich, at the Royal Concert Hall in Glasgow.

Around 28,000 civil service members of the PCS in Scotland will be participating.

Today's walkout follows that of last November when more than 1.5 million workers went on strike, described by the Prime Minister David Cameron as a "damp squib".

An estimated 400,000 people will protest at Westminster, including up to 16,000 off-duty police officers.

Members of the Scottish Police Federation will join their colleagues, who will don black caps to represent each officer expected to be lost under the Government's budget cuts.

The federation said it was "keen to support their colleagues who are facing unprecedented cuts in police numbers and pay and conditions south of the Border".

Mark Serwotka of the PCS union said the Coalition had cut tax for high earners while his members had seen thousands of their colleagues sacked, their pay frozen and were now being told they had to pay more and work up to eight years longer for smaller pensions.

"That's why hundreds of thousands of workers will be striking in opposition to the Government's prescription of austerity and misery that has plunged the UK back into recession," he added.

Dr Alan Robertson, chairman of the British Medical Association's Pension Committee, said doctors and other NHS staff had agreed changes to their pensions in 2008, which included increased contributions and a rise in the pension age.

"There is real anger among hard-working doctors about the way they have been treated. The Government must think again and reopen negotiations with the BMA so we can find a fair solution," he said.

Last night, Francis Maude, the Cabinet Office Minister, described the strike action as "futile" and said no-one would benefit.

Damian Green, the Immigration Minister, warned the public would find it unacceptable,

noting: "The security of the UK border is of the utmost importance and we will use contingency plans to ensure we minimise any disruption caused by planned union action.

"We are preparing to use our trained pool of backroom staff and Ministry of Defence police to boost staffing levels at ports and airports around the UK."

The strike action will once again throw the spotlight on comparisons between pensions in the public and private sectors.

Official figures show 66% of people in the private sector do not have a pension compared to just 16% in the public sector.

Those in the public sector are more likely to have final-salary pension schemes, receiving on average £7800 a year.

Those in the private sector mainly have schemes invested in the stock market, receiving on average just £1400 a year.

Tomorrow, the Coalition faces the prospect of more industrial strife as the threat of strike action by petrol tanker drivers could return with Unite due to reveal the result of a ballot.

On Friday, it must also announce any dates for industrial action to maintain its mandate for a strike. Earlier this week, Ed Davey, the Energy Secretary, briefed Cabinet colleagues on the contingency plans should a nationwide strike take place.

On Tuesday, reballoted tanker drivers at Hoyer, one of six companies involved in the dispute over industry standards, voted against strikes but in favour of other forms of industrial action.

Last month, forecourts ran out of petrol after Government ministers urged motorists to "top up" their tanks and stockpile fuel at home.