Outsourced university cleaners yesterday kicked off a three-day strike to stop a jobs cull and win improved pensions and union recognition.

More than 50 University of London workers were joined by students on picket lines at the gates of Senate House from 6am.

The mainly Spanish migrant workforce kept their spirits high and protest visible through a bitterly cold day by waving red flags and salsa dancing.

It was the latest phase of their "3Cosas" (which means three things in Spanish) campaign for sick pay, holidays and pensions.

After a two-day strike in November the workers won sick pay for absences of up to six months and 33 days of holiday per year.

But the pension provided by privateer Cofely GDF-Suez does not match the scheme offered to people employed directly by the university.

Cleaner Henry Lopez told the Star: "We managed to get some concessions from the company but they are still not the same as direct employees of the university.

"So we're still unequal in terms and conditions.

"We have the company pensions, which is nothing compared to the university pensions.

"We're all human beings at the end of the day and I believe that we work for the University of London and should be treated the same as their employees."

Workers are also concerned about a university plan to close its Cartwright Garden halls of residence that will threaten 90 jobs.

And they want privateer Cofely GDF-Suez to recognise the Independent Workers' Union of Great Britain (IWGB).

Their strike action will continue today with an open-top bus tour through London, stopping at sites connected to the university and the cleaning privateer.

In a briefing document the University of London said it recognised the TUC-affiliated Unison and UCU trade unions.

It added that outsourcing enables the university to "invest in its core purpose of providing excellent academic services to students."

That was dismissed by University of London Union vice-president Daniel Cooper, who said: "Their fight is our fight."