Billboard posters featuring quotes by Theresa May and Brexiter MPs have gone up around Dover as part of a “guerrilla advertising” campaign designed to embarrass pro-Brexit politicians using their own past claims and predictions.

A pro-remain group called Led By Donkeys has claimed responsibility for the posters, describing them as the latest in a “public information campaign to remind the public of the statements and promises made to us by our MPs”.

The latest posters – which also feature words from May, Jacob Rees-Mogg and Dominic Raab – include Liam Fox, who said in July 2017: “The free trade agreement that we will have to do with the European Union should be one of the easiest in human history.”

Dover, as with other towns and cities where more of the posters were expected to appear, was chosen for its significance, in its case due to being a “frontline” for the impact of Brexit, a spokesperson for the group told the Guardian.

The posters, which went up on Tuesday night in the port town, also included a Raab quote, for which he was ridiculed in November when he was Brexit secretary. He told an event: “I hadn’t quite understood the full extent of this, but if you look at the UK and look at how we trade in goods, we are particularly reliant on the Dover-Calais crossing.”

Those behind the group, which publicises its activities using the @ByDonkeys Twitter account, have chosen to remain anonymous but said the idea came from a chat in a pub among a group of friends in east London. WhatsApp has allowed those involved to organise with others around the country.

“The news cycle is just so fast now and people move on so quickly that people can forget what our leaders say,” the spokesperson said. “All we are doing is providing a public information service saying: ‘Stop a second and let’s remember what these people said before because they are currently on the bridge of the ship of state and we are sailing into chopping waters.’ We need to remember if they are qualified or not to take us on this journey and in many respects it’s clear they are not.”

The group has been posting quotes on Twitter and asking followers to choose their favourites. The most popular one was a Rees-Mogg statement from 2011: “We could have two referendums. As it happens, it might make more sense to have the second referendum after the renegotiation is completed.”

A tweet by Liam Fox. Photograph: @bydonkeys on Twitter/PA

Another chosen quote was from a speech given by May shortly before the referendum, in which she asserted that “remaining in the European Union means we will be more secure from crime and terrorism”.

A Dominic Raab tweet. Photograph: @bydonkeys on Twitter/PA

The spokesperson said the group had spent “four or five hundred quid” on the seven posters that had appeared to cover costs such as travel and materials, but added: “You won’t be surprised to hear that we haven’t necessarily asked permission to put them up and we are being discerning about the adverts that we cover up.”

Two of the Dover posters covered up McDonalds adverts, while the group changed its plans earlier this month after arriving at a billboard in Clapton, east London, to find it contained a feminist message. Another billboard was chosen instead.

The spokesperson insisted that those involved were not affiliated to any of the Brexit groups, although the group’s number included some with “experience of campaigns.”

They added: “We don’t have money to do a national advertising campaign. We have spare time, a ladder and maybe a little smidgen of wit. The treasure trove of historic verbal incompetence by our Brexit leaders makes this a relatively easy campaign to sustain.”

The first poster went up in early January in Stoke Newington, north-east London, and featured David Cameron’s tweet before the 2015 election in which he claimed: “Britain faces a simple and inescapable choice – stability and strong government with me, or chaos with Ed Miliband.”

The spokesperson said: “The idea – like most half-decent ideas – came in a chat down the pub. We were talking about whether Cameron would one day delete his ‘chaos with Ed Miliband’ tweet, and someone said: ‘Let’s turn it into a tweet you can’t delete.’ It went from there.”

It was followed by a poster in Clapton, also in east London, featuring David Davis. The campaign then spread to leave-voting country with a poster featuring a Michael Gove quote being pasted on a billboard in Romford, Essex.

Boris Johnson would feature in the next manifestation of the campaign, according to the group, which described the former foreign secretary as “a treasure trove of hypocritical piffle”.