The Wombles: Anarchists with padding
The May Day protests have attracted a diverse range of supporters.
Here are some of the groups who are expected to take part this year.
The acronym stands for White Overall Movement Building Liberation through Effective Struggle.
Wombles are recognisable because they wear white overalls and often strap padding to their body because they say they will be roughly treated by the police.
This is a direct action anarchist movement based on Ya Basta! - the non-violent protest group which originated in Italy. But they also say they are part of the vanguard against "repressive police tactics".
There is no leadership and tactics are agreed at meetings. The Wombles say they promote "anarchist ideas, libertarian solidarity, autonomous self-organisation and humour."
The Wombles say this May Day is their chance to "fight back" and turn May Day protests into "weapons of mass construction".
The groups official website encourages people to join the organisation - but warns that "scum like journalists and pigs" may infiltrate their meetings.
A loosely-organised cycle group which campaigns for better public transport and an end to car culture.
Meetings involve cyclists from around London getting together on one evening a month and holding a protest ride through a congested part of the city.
May Day map of London
Events, locations and times
The protest rides attract a wide-range of supporters in London who want to see more done to improve two-wheeled commuting.
This year's May Day protest ride is expected to start at 11am on the south bank of the Thames and wind its way very slowly up through Westminster. The cyclists will then reassemble after lunch for a second ride which is expected to end at the headquarters of oil company Shell.
Trades Union Congress:
The TUC has 70 member unions representing nearly seven million working people in the UK and is an original organiser of May Day demonstrations.
TUC: Original May Day march
Its mantra is to "campaign for a fair deal at work and for social justice at home and abroad".
It is calling for a "peaceful celebration" of International Workers' Day.
An estimated 10,000 trade unionists will march through Central London from Clerkenwell Green to Trafalgar Square.
There, a rally will hear speakers including Labour MPs, senior political figures such as Tony Benn and senior trade unionists from Britain and abroad.
London Animal Action:
An animal liberation group which campaigns against the fur trade, this group says it will protest outside fashion retailer Dolce & Gabanna in Old Bond Street in the West End.
However, a promised protest on last year's May Day failed to materialise.
According to the main organising website of the May Day protests, protesters will "combat trouserism" with a run for freedom to the British Museum.
Campaigners who support a controversial documentary into deaths in custody are planning to picket Channel Four.
The television channel refuses to show the film - so the protestors say they are going to show the film on the side of the company's headquarters.