© George Henton/Barcroft MediaRevellers mark Margaret Thatcher's death in Brixton, south London.
Parties to be held across the UK including in Trafalgar Square, scene of poll tax riots

While many were mourning the passing of Margaret Thatcher, others were planning celebrations for the day of her funeral. Many have called for a pre-funeral gathering at Trafalgar Square on Saturday to mark her death with revelry.

Facebook pages were linking to a leftwing site where a party to mark Thatcher's death had been proposed since 2004, urging people to turn up from 6pm on Saturday in Trafalgar Square, where the most violent poll tax riots took place in 1990.

The post on the leftwing website Indy Media calls for people to gather on the first Saturday after Thatcher's death. It states: "We all know it can't be long now - and when Margaret Thatcher dies its party time! On the first Saturday after Margaret Thatcher dies, Class War is calling a mass party to start at 6pm, in Trafalgar Square, scene of the most famous riot against her policies! Whether or not you want to reminisce about the good old days of rioting against the poll tax, to toast old friends who fought Thatcherism, or just want to celebrate the death of the most reviled woman in Britain, we hope to see you there. Bring your champagne, fireworks, party clothes and yourselves!"

A campaign has also been launched to make Ding Dong! The Witch is Dead reach No 1 in the music charts.

In Liverpool, where Thatcher was deeply unpopular among many residents because of her role in the closing of the docks and response to the Hillsborough disaster, plans were already being made. The Liverpool Echo created a wordcloud of tweets, comments on articles and the Echo's Facebook page relating to Thatcher, with the words "party", "good riddance", and "Maggie" featuring prominently.

Some had started to organise parties on Twitter, where the user @LFC_Banners called for people to gather on the day of the funeral at St George's Hall and to "bring a bottle". Linked to the tweet was a picture of a banner featuring the slogan "We're Going to Have A Party"and a picture of the grim reaper. For several years "We're going to have a party/When Maggie Thatcher dies" has been a common chant by some Liverpool Football Club fans, who have been critical of Thatcher's perceived role in the cover-up of the Hillsborough disaster. One Liverpool resident tweeted: "Everyone north of Watford, 17th April, your town or city centre, wear bright colours, bring a bevvy", marking it with the hash tag #KneesUpTime.

Facebook sites have been set up to organise parties with a range of names including "We're having a party when Thatcher dies", which had attracted more than 6,000 likes and featured the phrase: "It's gonna be one hell of a session!! Ding-Dong when the bitch is dead!!" Another was called "When Thatcher dies ... I'm going to celebrate with a glass of milk!", which featured the exhortation: "Unite and invite!!! our childish bones were brittle because of this woman."

Almost 200,000 people had "liked" the Is Thatcher Dead Yet? website, which had been updated with a large block-capital "Yes" and added: "This lady's not returning."

The website Red Pepper posted five songs to play at Thatcher's funeral, which included The Larks' Maggie Maggie Maggie (Out Out Out), Hefner's The Day That Thatcher Dies and Elvis Costello's Tramp the Dirt Down.

On the evening of the former prime minister's death, parties attracting hundreds of revellers were held in several cities across the UK, with arrests made in Brixton, south London, and Bristol. One officer was taken to hospital, five others were injured and one man was arrested in clashes in Bristol after a street party turned violent.

In Brixton, people gathered from around 5.30pm in Windrush Square and by nightfall had attracted about 200 protesters after a party was announced on Facebook. The Ritzy cinema was festooned in banners, with the "now showing" sign rearranged to spell out "Margaret Thatcher dead". One banner read: "Rejoice, Thatcher is dead." Others chanted: "Maggie, Maggie, Maggie, dead, dead, dead." The Metropolitan police said there had been low-level disorder in Brixton. Two women were arrested on suspicion of burglary after a shop front was broken.

In Leeds, a group handed out "Thatcher's dead cake", singing and cheering at one of several street parties, while in Liverpool there was a gathering lit by red flares on the steps of Lime Street station. Police said they had not been called to any disturbances in the city related to the former prime minister's death.

Around 300 people gathered in Glasgow's George Square, which experienced highly charged poll tax protests in 1989, after the introduction of one of Thatcher's most divisive measures. Revellers wore party hats and popped a bottle of champagne while streamers were thrown into the sky. In Derry and Belfast, there were republican celebrations. In one incident in Derry a petrol bomb was thrown at a passing police patrol near Free Derry Corner during a street party. In the Falls Road area of west Belfast, car horns were sounded and champagne bottles cracked open as hundreds gathered to wave flags and chant.

In Trafalgar Square, central London, champagne bottles were passed around as people celebrated.