Up to 750,000 civil servants, teachers and lecturers began strike action over proposed penion changes today in co-ordinated action affecting schools, courts, job-centres and airports.

Around 8,000 schools, one third of the national total are closed with Liverpool, Newcastle among the worst hit with around three quarters of institutions affected. Nearly half of schools in Manchester and Birmingham as well as two-thirds of universities and colleges are also affected.

Police leave has been cancelled in London and the Public and Commercial Services (PCS) union, some 14,000 of whose members work for the UK Border Agency have warned of a backlog of passenger delays at Heathrow, Gatwick and Manchester airport and the port of Dover.

Debating on the BBC Today programme this morning, Cabinet Office minister Francis Maude and Mark Serwotka, general secretary of the PCS clashed over the nationwide protests.

Mr Serwotka said the government's unwillingness to 'move a jot' on the key recommendation's of Lord Hutton’s report – increasing the retirement age to 66, average contribution increases of 3%, pension reductions and aligning the inflation measure from CPI to RPI – was forcing the union's hand.

Mr Maude faced sustained questioning on whether the current system was in fact affordable long-term, based on findings from the National Audit Office and the Public Accounts Committee indicating changes made in 2007-2008 had stabilised the cost of pensions at 1% of GDP.

Defending the government's position Mr Maude accused the unions involved in today's strike of having 'jumped the gun' and taken 'premature action'.

Stating the government's intent to protect the lower paid, he said at the end of the process, most public sector workers should receive pensions that are at least as good as they are today.

Mr Maude added:'But we do want them to pay some more, so that there is a better balance between what they pay and what other taxpayers pay.'