The piece is called “Keep Ou” and has the words written over a shuttered EU arrivals gate.
The “T” of the word “Out” has fallen off and is being used as a hammer by a rat to try to break the gate’s padlock open.
Banksy used a real customs arch for the piece which was salvaged from Heathrow airport, according to the Royal Academy.
The piece is not the first time the anonymous artist has subtly criticised the decision to leave the EU.
In last year’s display he produced an altered Vote to Leave placard altered to read “Vote to Love”, featuring a red heart-shaped balloon.
The artist’s works are frequently political. He has produced works criticising the response to the 2015 European immigration crisis, climate change sceptics and the treatment of refugees.
The 251st summer exhibition is curated by painter Jock McFadyen and features artists including Polly Morgan, Charles Avery and Mat Collishaw.
The event is the world’s largest open submission contemporary art show, meaning anyone can submit a piece to be considered.
Many of the displayed works are for sale, with some funds going towards the Royal Academy’s fine art school.
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