A Birmingham MP has joined a picket line outside the House of Commons.

But Lynne Jones (Lab Selly Oak) was not on strike herself. Instead, she was backing Commons cleaners taking industrial action in protest at low pay.

Scores of cleaners mounted picket lines at six entrances to the Commons and Lords as part of a protest against "poverty" pay rates and poor working conditions.

The Transport and General Workers Union, which organised the protest, warned MPs and Lords they would have to clean their own offices and toilets because of further industrial action unless the dispute was settled.

About 170 cleaners took part in the 24- hour

walkout, which is expected to be followed by further strikes later in the year.

Dozens stood outside the main entrance to the Commons brandishing mops and banners and chanting "low pay, no way" and "cleaners united will never be defeated".

The historic strike was in protest at an hourly pay rate of £5 an hour, which the cleaners said was impossible to live on in central London.

Staff are angry about a two- tier system which means some workers get more than others for doing the same job. The 170 staff employed by two agencies, Emprise Services and Mitie Cleaning, earn just £5 an hour, with no sick pay or pension and just 12 days holiday a year.

But workers employed directly by Parliament earn £8 an hour with sick pay, a full pension, and six weeks' holiday.

As a backbench MP, Dr Jones earns a wage of £59,095 a year.

She said: "I am concerned that these services are contracted out at all."

Tony Blair, asked about the dispute during Prime Minister's Questions, said it was a matter for the House authorities.

Jack Dromey, deputy general secretary of the TGWU, said: "What is going on inside Parliament is a national scandal. Parliament is paying poverty wages, which is shameful." Further industrial action would follow, he warned.

"If the cleaners do not get justice, they will strike again and again.

"MPs and Lords better get used to cleaning their own offices and toilets."

One of the cleaners, Tesfaalen Gebru, aged 43, said he had two cleaning jobs at the Commons to earn a decent wage. He cleaned kitchens during the night and then cleared rubbish during the day, working a 64 hour week.

The cleaners are calling for a "London living wage" of £6.70 an hour and say they want sick pay and better holidays.

MPs backing the strike include David Winnick, Paul Keetch (Lab Hereford), John Hemming (Lib Dem Yardley), Ian Austin (Lab Dudley N), Rob Marris (Lab Wolverhampton SW), Lynda Waltho (Lab Stourbridge), Ken Purchase ( Lab Wolverhampton North East), Lorely Burt (Lib Dem Solihull), Clare Short (Lab Ladywood), Joan Walley (Lab Stoke North), Mark Pritchard (Con The Wrekin).