This is just a list of free and open spaces in London, places where smallish groups might congregate to do something, like talk, understand things better, make plans, organise other things.

Please add your favourite such places - the constraints are that they should be open to the public with no entrance fee. Err... and usable as a gathering, organising space.

Please also add detail of particularly useful parts (speakers corner in Hyde Park for example) and if this inspires you to do something else, please leave a note pointing to it. My initial categorisation might also be a bit rubbish - if there's a better way without making things too complicated, feel free to tinker.

West End

Hyde Park

Green Park

St James's Park

Kensington Gardens

Grosvenor Square

Cavendish Square

Bedford Square

Red Lion Square

British Museum

Science Museum

Natural History Museum

Victoria & Albert Museum

National Gallery [there's a nice cafe in there which we could hang out in]

Trafalgar Square (though it's a bit touristy!)

Soho Sq.

Golden Sq.

Primrose Hill and Hampstead Heath (West End at a Stretch but serviced 'well' by the Nth. Line)

City

Liverpool Street Station

Broadgate

Finsbury Square

Hoxton Square

Truman brewery - lots of places to sit and free wifi

Paternoster Square (St Pauls)

Barbican Centre (and free wifi) [and indoor and outdoor space]

Riverside

Tate Modern 

South Bank Centre

London Assembley

Bermondsey riverside and design museum area

Victoria Park (next to Westminster)

St Katherines Dock

Battersea Park (I like it by the Pagoda)

[are there any squares in Pimlico?]

Embankment Gardens