How many people demonstrated on Saturday in the March for the Alternative anti-cuts march?

Estimates range from 250,000 to 400,000 - and these figures are always controversial. But in the pantheon of major demonstrations going through London, the march is near the top.

Counting march numbers is a difficult business. Official efforts go from taking an area of the march, counting the numbers in it and then extrapolating that to the whole length of the march. Other times - see the Countryside Alliance march of 2002 - protesters are counted as they pass a specific point. Either way, teh size of a demonstration can mark its success or not. But the reality is, no-one really knows. The 2003 Stop the War march brought any nubmer from 750,000 to 2m to the streets of London - the latter figure calculated by extrapolating an ICM poll of the number of people who said they had attended.

We've worked out some of the data for the major marches in the UK, going back to Aldermaston in the 1950s. It's not a complete list - let us know what you would add to it.

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Data summary

Major UK demonstrations Click heading to sort. Download this data ID Date Protest Organisers Cause Location Organisers/ others estimate Police estimate (where known) % Difference 1 April 4, 1958. Aldermaston march Campaign for Nuclear Disarmament Nuclear weapons London to Berkshire 2,000 2,000 0 2 March 28, 1959. Aldermaston march Campaign for Nuclear Disarmament Nuclear weapons London to Berkshire 60,000 60,000 0 3 April 1, 1961. Aldermaston march Campaign for Nuclear Disarmament Nuclear weapons London to Berkshire 150,000 150,000 0 4 March 17, 1968. Grosvenor Square, peace march Vietnam Solidarity Campaign Vietnam War London 80,000 10,000 700 5 October 27, 1968. Grosvenor Square, peace march Vietnam Solidarity Campaign Vietnam War London 200,000 50,000 300 6 October 24, 1981. CND march for peace Campaign for Nuclear Disarmament Nuclear weapons London 250,000 250,000 0 7 October 22, 1983. CND march for peace Campaign for Nuclear Disarmament Nuclear weapons London 400,000 200,000 100 8 March 31, 1990. Poll tax All Britain anti-Poll Tax Federation Poll tax London 200,000 40,000 400 9 May 1, 2001. May day protest Various groups Globalisation London 10,000 5,000 100 10 November 18, 2001. Stop the war Stop the war coalition Afghanistan London 100,000 15,000 567 11 September 23, 2002. Liberty & Livelihood Countryside Alliance Hunting and countryside causes London 407,791 400000 2 12 February 15, 2003. Stop the War Stop the War coalition Iraq London 2,000,000 750,000 167 13 February 15, 2003. Stop the War Stop the War coalition Iraq Glasgow 100,000 50,000 100 14 January 31, 2009. Tamil Eelam British Tamil Forum Tamil rights London 100,000 50,000 100 15 March 28, 2009. March for Jobs, Justice & Climate Put People First G20 London 35,000 35,000 0 16 November 10, 2010. Fund Our Future: Stop Education Cuts National Union of Students Education cuts London 52,000 30,000 73 17 December 9, 2010. Tuition fees protest, Parliament Square National Union of Students, University of London Union (ULU) and the National Campaign Against Fees and Cuts (NCAFC) Tuition fees London 30,000 15,000 100 18 March 26, 2011.. March for the Alternative Trades Union Congress Cuts London 400,000 250,000 60

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