Thousands protest over pensions
Scotland Yard has been forced to pull officers off the beat to cover for nine in 10 emergency call handlers who joined the public sector strikes.
All police leave in the capital was cancelled to help cope with the walkouts by civilian staff. Officers were also policing as union leaders and thousands of activists took part in a march, followed by a rally in Westminster.
By 2pm, police had arrested 18 people at the protest for a variety of offences including possession of drugs, criminal damage and breach of the peace.
Among the buildings being picketed in London were Parliament, the Royal Courts of Justice in central London, many courts including Westminster magistrates, and the headquarters of the education and business departments.
Immigration officers at ports and airports across the UK joined the strike, with the prospect of long delays for travellers returning to the country.
In Liverpool, thousands of protesters marched from William Brown Street to Chinatown for a rally, carrying placards, flags and leaflets bearing slogans like: "Fight the Cuts!" and "Unity is Strength." Strikers blew whistles and chanted: "No ifs, no buts, no public sector cuts."
A carnival atmosphere pervaded in Brighton and Hove as more than 1,600 striking public sector workers marched in opposition to the Government's plans. People young and old banged drums, waved flags and banners, and listened to music from a stage set up on The Level near the city centre. From there they marched through the streets to Hove Town Hall for a rally highlighting discontent at Government plans to raise pension contributions and increase the retirement age.
Around 1,500 people gathered in the centre of Sheffield for a rally, march and even a sing-song. A series of speakers addressed the crowd from the steps of the City Hall before The Sheffield Socialist Choir led a good natured sing-a-long and the mass of teachers, civil servants and students moved off for a mile-long circuit of the city centre.
Up to 6,000 people joined the pensions protest through Newcastle city centre, a union leader said. With one in three North Easterners working in the public sector, many people felt Government cuts were having a greater impact in the region than elsewhere.
In Manchester's busy Oxford Road, passing motorists blew their horns in support as hundreds of teachers, civil servants and protesters mustered for a march and rally in the city centre. Police and unions had expected around 500 marchers, but numbers appeared to be well up on that figure.