Public service workers are threatening a summer of discontent just as the general election campaign enters a new phase.

Several key public sector unions are balloting members over a range of issues including pensions and pay.

Members of NATFHE, the university and college lecturers' union, will be balloted on a recommendation to take strike action over government plans which the union says will seriously worsen the pensions of thousands of lecturers.

According to the union, younger lecturers and future entrants would suffer significantly - a current lecturer, now 35, expecting to retire at 60 after 30 years of lecturing could lose 12 per cent of total pension benefits.

And new lecturers starting in 2006 could lose as much as 23 per cent of the total pension benefits which an equivalent lecturer can currently expect, it warns.

NATFHE was also set to publish the results of a ballot of members on possible strike action over claims that further education colleges have failed to fully implement a nationally agreed pay deal.

Meanwhile, Unison general secretary Dave Prentis was on Monday presenting a Valentine's Day card to MPs asking them for their support in the campaign to defend public service pensions.

Unison is also sending out ballot papers to 800,000 of its council members on whether to take industrial action in protest of changes to their pension scheme and retirement age.

In a separate move that could boost union power, the executive of the GMB union is expected to consider an invitation to merge with the T&G and Amicus unions.

A sign of the widescale anger the government is provoking in the union movement will come on Friday when the unions stage a nationwide day of campaigning to protest against the pensions changes.

TUC general secretary Brendan Barber said: "There is enormous concern at the impact these proposals will have upon the lives of millions of public sector workers.

"We are determined to keep up the pressure on the government."

Events are planned in places including Newcastle, Leeds, Swansea, Cardiff and Gloucestershire among others.