[The below is from Tim Hardy, an activist and writer from London interested in the role of technology in driving social and political change, editor of Beyond Clicktivism and member of Sukey.]

This Saturday, hundreds of thousands will gather in the UK capital to demonstrate against shock doctrine tactics from a Conservative-led government. Not only has the finance industry walked away scott free after destroying the economy but the damage they caused is being used by the party they fund to push back the hard-won gains of a century in society's care for its most vulnerable. They claim there is no alternative. We are demonstrating because that is not true.

A giant wooden horse will appear at Camberwell in south London in the morning. A critical mass of cyclists will form in the east. Slowly from all points of the compass, weird and wonderful groups of protesters will begin to coalesce in what promises to be a spectacular day of demonstrations that may go on all night.

The Trade Union Congress who are organising the main event know of more than 600 coaches and nine special trains bringing demonstrators from around the country – and of one person who is walking from Cardiff. A recent protest organised on Facebook in Portugal mobilised nearly half a million people at short notice. It is not unreasonable to imagine that numbers might reach a million.

The itinerary of the official march is to form at Victoria Embankment from 11am then to set off to Hyde Park for a rally starting at around 1:30 and continuing until around 4:30pm. Among the marchers following the official route will be blocs including 6 Billion Ways, Buggy bloc (for people with children), the Green Party, the Quakers, Women's bloc and the Woodcraft Folk.

The unions have been working hard to make access easier but for those who cannot physically make the day, Disabled People Against Cuts are also offering the chance to make your presence felt through a virtual protest map.

There are also several feeder marches starting from different areas of London and ending at Hyde Park, none officially recognised by the TUC. The largest will be the Education Bloc from ULU and the South London feeder march, from Kennington Park. The best sources for information on the feeder marches and blocs are Political Dynamite and Freedom Press.

On the fringes of the march, theatre activists will invite people to take part in alternative reality games using exercises drawn from the Brazilian Theatre of the Oppressed.

Sukey will be doing its best to keep people safe, mobile and informed on the day with live map updates showing kettles and blocked roads, a smartphone app and free SMS service. If the police do use the controversial technique of kettling, then SOAS University students will be maintaining a Kettle Cafe to provide people with food and water within the containment zones.

Indy Media London will be providing their news service with rss access to updates. VisionOn.TV will be offering a platform for video journalists to share their reports. Dissident Island and Resonance 104.4 FM will be providing radio coverage of the day.

At most festivals, the most interesting things occur at the fringe and the same is true for the 26 March.

At 2.00pm the crowds will begin to quieten, shushing one another until an eerie silence is achieved. Then at 2.10pm from the distance the sounds of World War 2 air raid sirens will begin, growing louder until 2.11pm when everybody is encouraged to make as much noise as they possibly can as hundreds, maybe thousands split off for a range of direct actions around London.

These include UK Uncut who will Occupy for the Alternative, targeting tax dodging banks and shops on Oxford Street whose legal exemptions, if stopped, would pay for the services being destroyed. Many other actions will become apparent on the day.

Don't think that when the speeches end at 4.30pm it's time to go home.

Battle of Britain themed parties with bunting, tea and cakes will be served from 5pm at key points on the map. As night falls, activists will seek to turn Trafalgar Square into Tahrir Square and Occupy Hyde Park for 24 hours. Mass sleep outs to protest at Westminster Council's planned criminalisation of homelessness will also be occurring.

Make your voice heard, stay safe, bring your sleeping bag – and don't forget to keep your eye out for the pirate cinema!