Image caption The 1.1 million member ballot was the biggest in the history of UK industrial relations

Members of the Unison trade union have voted in favour of striking against the government's plans to change public service pension schemes.

There was a 78% majority, with 245,358 in favour and 70,253 against on a 29% turnout.

The vote means there is likely to be a huge national strike on 30 November.

On Wednesday, the government offered to change its plans, which are aimed at cutting the cost of funding public service pensions.

Following the ballot result, the Cabinet Office Minister Francis Maude called on Unison members not to go ahead with a strike.

"We listened to the concerns of public sector workers about their pensions and yesterday responded with a new generous settlement which is beyond the dreams of most private [sector] employees."

"Today's Unison ballot received a very low turnout - with less than a third of their members even voting - which shows there is extremely limited support for the kind of strike action their union leaders want," he added.

However, the government's changes to its original plans have met with only a lukewarm response from public sector unions.

We still have had no offer in those negotiations Dave Prentis, Unison general secretary

Unison general secretary Dave Prentis said: "Yesterday's statement in Parliament was a marked improvement on earlier proposals."

"But it is important to understand that the statement has to be translated into offers in the scheme-specific talks.

"We still have had no offer in those negotiations, where such an offer can legitimately be made," he added.

Combined action

The 30 November "day of action" is being co-ordinated by the TUC and could involve members of 20 trade unions in the public sector.

Media playback is unsupported on your device Media caption Dave Prentis: ''There has been no offer whatsoever... what we had over the last 48 hours was as statement of principles by government''

Five already have a mandate for action from earlier this year, while the others are still in the process of balloting their members.

If they all vote in favour of action, then the day may turn into the biggest co-ordinated strike since 22 January, 1979.

Then, during the so-called "winter of discontent", four big public sector unions held a strike in pursuit of a pay rise above the then Labour government's 5% ceiling.

As well as many NHS and local government staff, Unison represents police staff (though not police officers), probation officers, and clerical and ancillary staff in schools, colleges and universities, who are all in the local government pension scheme.

Some civil servants across the UK took part in a pension strike in June this year.

They were joined by many teachers and further education lecturers in England and Wales, and the next strike is likely to involve them all again.

Changes planned

The government's pension plans have been largely inspired by Lord Hutton's independent inquiry into the rising cost of public service pensions.

He suggested that most staff should pay higher contributions, with the increases being phased in during the next three years.

Then, from 2015, most current staff and all new recruits will be offered career-average schemes instead of the more expensive, mainly final-salary, versions now on offer.

These new schemes will typically involve staff working to later pension ages, which in turn will rise in step with the state pension age.

The government has made it clear all along that it wants public employees to work longer, and pay more.

But it argues that for most staff the pensions they receive will be the same as before, or even better.

Negotiations with trade unions have been taking place over the past few months, and more are scheduled, but there has been no agreement so far.