Led By Donkeys is a British political campaign group established in December 2018 as an anti-Brexit group, but which has also criticised other actions of the Conservative government. After the 2024 election of a Labour government, it defined itself as an "accountability project" and stated that the Labour government was also fair game.

Since the group's creation its four founders have been calling out what they call "thermonuclear hypocrisy" and used satire targeted at pro-Brexit politicians. Led By Donkeys' main campaign consists of hoardings containing past X posts by pro-Brexit politicians, or quotes presented as tweets. These tweets state the politicians' previous political positions, which according to the group have not stood the test of time.

The campaign was initially run as a guerilla operation, in which Led By Donkeys posters were plastered over existing adverts. It was then expanded into a crowdfunded campaign that purchased advertising space on hundreds of billboards across the UK. Later the group staged real-life stunts, including projecting messages on iconic places including the Houses of Parliament and the White Cliffs of Dover, carving giant messages on beaches and fields, and directing crowds to unfurl huge flags at pro-European Union marches. Videos of these messages were subsequently viewed millions of times on social media. The campaign group won the award for Best Social Media Campaign in the 2019 Social Purpose Awards, and won gold in the National Social Impact category in the 2020 Outdoor Media Awards.

The group's name comes from the phrase "lions led by donkeys", referring to British soldiers in the First World War, who were led to their deaths by leaders deemed incompetent and indifferent.

In the Conservative Party's manifesto for the general election in May 2015, the party promised a referendum on the UK's European Union membership by the end of 2017. In the 2016 referendum voters voted by 52% to 48% to leave the European Union. By December 2018 the UK had not yet left.

In December 2018, four friends were discussing their frustrations with the ongoing Brexit situation in The Birdcage, a pub in Stoke Newington. All four men had a connection with environmental campaign group Greenpeace; Oliver Knowles and Ben Stewart were employees, and James Sadri and Will Rose had previously been involved with the group. In the referendum, they had all voted to remain in the EU. During this period, the group discovered an old tweet by former prime minister David Cameron. This tweet, dating from before the 2015 election, read "Britain faces a simple and inescapable choice - stability and strong Government with me, or chaos with Ed Miliband". They agreed it would be a shame if Cameron deleted it, as in their view it summed up the "failure of Britain's political leadership". They were also frustrated by the failure, in their opinion, of British media to hold leaders of the Brexit campaign to account. They decided to preserve the tweet by printing it out and pasting it up. Each of them chose a statement from a pro-Brexit politician to go up on billboards as well as "tweets you can't delete", looking for the "most offensive lies, lunacy and hypocrisy" in their view. They settled on the following four old claims: "The day after we vote to leave we hold all the cards and can choose the path we want" (Michael Gove, April 2016); "The Free Trade Agreement that we will do with the European Union should be one of the easiest in human history" (Liam Fox, July 2017); "There will be no downside to Brexit, only a considerable upside" (David Davis, October 2016); "Getting out of the EU can be quick and easy – the UK holds most of the cards in any negotiation" (John Redwood, July 2016). Two years later, by Christmas 2018, with prime minister Theresa May's Brexit deal stuck in parliament, none of these claims had materialised, according to The Guardian.

Rose designed the posters. Sadri came up with the name "Lions led by donkeys", a common phrase referring to soldiers in the First World War who were led to their deaths by incompetent and indifferent leaders. They thought it well described the relationship between the British people and their Brexit leaders. Rose shortened it to #LedByDonkeys. They had the five tweets printed at billboard size. The activists bought a ladder, high-visibility jackets to look legitimate, a bucket, a roller and wallpaper paste. On the night of 8 January 2019 they illegally plastered the David Cameron tweet over a finance advert on a billboard on the A10 in Stoke Newington. They posted a photo of the billboard to their new Twitter account, and asked journalist Marina Hyde of The Guardian to retweet it; this soon resulted in hashtag #LedByDonkeys trending on Twitter. Within a day, their billboard poster had been plastered over with blue paper.

In the time between their day jobs and their family life, at night the group illegally pasted the other four original tweets on billboards around London. The group stated that one of their aims was to spark a discussion amongst Leave voters about the promises of the leading Brexiteers. They therefore chose Dover, a pro-Brexit constituency, as their next location. They selected four additional historical Brexiteer statements, partially from suggestions made by their social media followers, among which was Dominic Raab's 2018 statement "I hadn't quite understood the full extent of this but ... we are particularly reliant on the Dover-Calais crossing". On 16 January 2019 the group tweeted photos of the four Dover billboards, along with the message "A busy night on the Brexit frontline. We've covered Dover in the historic quotes of the people responsible for this chaos. Britain is a nation #LedByDonkeys." The group later stated that this was the moment when they went viral. The next day all four posters were removed by the billboard company.