An inflatable boat with dummy migrants which was launched onto the crowd at Glastonbury during a gig was let loose by Banksy.
Idles, who were performing a set when the incident took place, say they were unaware of the stunt until they left the stage.
During last night's set, the rock band also led the Glastonbury crowd in chanting 'f*** the king' as the festival turned political with the band's vocalist Joe Talbot also singing an 'anti-Farage song'.
Banksy has previously been rumoured to be involved in a woke new stage that celebrates immigration to the UK and declared that 'no human is illegal'.
Idles' politically-charged performance was just one of a number of statements made during the third day of the festival in Somerset.
Blur frontman Damon Albarn discussed Gaza and suggested Joe Biden was too old to be president during his surprise appearance at Worthy Farm.
A blow-up small boat surfs the crowd during the performance by Idles at Glastonbury
Rock band Idles led the Glastonbury crowd in chanting 'f*** the king' as the festival turned political on Friday night
The band's vocalist Joe Talbot also sang an 'anti-Farage song' while a small blow-up boat surfed the crowd in a pro-immigration protest
Talbot is the frontman of British rock band Idles
It came as Welsh singer Charlotte Church also sang 'free Palestine' and wore a keffiyeh as she led an improvised number with the audience.
Albarn came on stage to accompany indie band Bombay Bicycle Club for their song Heaven, on which he features for their latest album.
He was met with cheers of approval by a crowd of thousands as he made three political statements.
'It's very nice to be here thank you - thank you to Jack and everybody,' Albarn said.
'Three things - you have to show me how you feel about it - are you pro Palestine? Do you feel that's an unfair war?
'The importance of voting next week - I don't blame you for being ambivalent about that, but it's still really important.
'And thirdly - maybe it's time we stopped putting octogenarians in charge of the whole world?'
The latter appeared to be a reference to the 81-year-old Mr Biden, who has faced fierce criticism over his performance in a debate against Donald Trump.
Meanwhile Charlotte Church sang 'free Palestine' with a crowd of hundreds as she led an improvised number with the audience during an intimate and politically charged appearance at Glastonbury Festival.
The Welsh singer's performance at Worthy Farm comes months after she said police had to check on her because her safety and that of her family has been threatened after she took part in a pro-Palestine march in London.
The 38-year-old, who strongly denied claims of antisemitism at the time and voiced her support for Jewish people, joined Billy Bragg's Radical Round Up at Worthy Farm's Left Field stage on Friday.
Wearing a long red dress, Church also had a keffiyeh, a traditional Arab headdress which has become a symbol of Palestine, over her shoulder.
'Hiya babes - lots of love from Wales my darlings,' Church said as she greeted the crowd.
'I sort of want to give you the mic today... there's so much untapped singing potential in you guys which we're going to explore.'
Talbot swings his microphone around on the Other Stage at Glastonbury
Guitarist Lee Kiernan crowd-surfs during the Idles' headline set at Glastonbury
Idles' politically-charged performance was just one of a number of statements made during the third day of the festival in Somerset
Pictured: Damon Albarn performs with The Bombay Bicycle Club on The Other Stage
Blur frontman Damon Albarn discussed Gaza and suggested Joe Biden was too old to be president during his surprise appearance at Worthy Farm
Charlotte Church performs on the Left Field stage during the Glastonbury Festival at Worthy Farm in Somerset
Church told the crowd she would lead them in collaborative vocal improvisation, seeing her improvise lyrics over a chorus of humming from the audience.
'It's Friday at Glastonbury, all the adventures you're going to have and the things you'll see, music, dance and sing,' Church's improvisation began.
'The spirit of expression... and now you can say that you performed at Glastonbury, sing it to me now.'