Today's May Day marches through the British capital have been mostly peaceful.
As the main march by some 3,000 trades unionists reached London's Trafalgar Square for speeches, there were small sporadic protests elsewhere in the city but little disruption.
Scuffles broke out between protestors and police during a demonstration at the Lockheed Martin offices in central London.
Around 300 demonstrators staged a sit-in on the road outside the offices of the giant US firm in High Holborn.
Scuffles broke out as police tried to move the protesters along.
Four thousand police were deployed in central London ahead of today's demonstrations.
Other organisers of today's marches in London included animal rights activists, students protesting against university fees, anti-pollution campaigners, anarchists and anti-war groups.
Dublin's main May Day protest is due to start at 6.30pm at the Garden of Remembrance on Parnell Square. The Irish Anti-War movement is holding a short rally on the centre island on O'Connell St from 6pm, before joining the main rally.
Clashes between police and demonstrators occurred overnight in Berlin at a May Day rally.
Water cannon was used when violence broke out on the fringes of a peace rally that had attracted around 6,000 people to a park in the eastern part of the German capital.
Considerable numbers of police in riot gear took two hours to bring a crowd of about 200 under control, said a police spokesman.
One policeman was seriously injured and 97 people arrested, the source told AFP. The rally at the Mauerpark is held every year on 1 May.
Elsewhere, Turkish riot police have detained some 30 left-wing protestors who gathered in Istanbul to mark May Day.
Calling the protest illegal, truncheon-wielding police swooped on the demonstrators in centrally located Taksim square on the city's European side after they refused to disperse.
In Asia, May Day rallies have been muted due to concerns over the spread of SARS. More than 5,600 people worldwide have been infected by the virus, with 377 succumbing to it.
In China, where May Day is enshrined in the national psyche, celebrations were quiet and demonstrations were banned as SARS continued to ravage the country.
A day after the 159th Chinese SARS death was announced, Beijing's ceremonial, political and social hub, Tiananmen Square, was eerily quiet.
Rallies in Hong Kong, Malaysia and Indonesia were told of fears for jobs due to the economic consequences of the spread of the virus that causes SARS.
Thousands hit the streets of Indonesian cities to mark May Day, calling for the resignation of President Megawati Sukarnoputri and her manpower minister for alleged indifference to the plight of workers.
A similar scene was played out in Moscow, with thousands of Communists demanding the resignation of President Vladimir Putin's government.
