In October of 2018, the UK government announced the Festival of Great Britain and Northern Ireland which it calls
A major nationwide festival showcasing the UK’s unique strengths in creativity and innovation will be held in 2022.
The announcement by the government and a BBC article on the matter do not mention Brexit.
On the other hand, articles by CNN and the FT and an opinion column in the Guardian do mention it:
CNN: May's plan for a Brexit festival flops on social media:
UK Prime Minister Theresa May announced plans to hold a nationwide festival in 2022 to celebrate Britain's scheduled departure from the European Union next year
The FT Theresa May plans celebratory Brexit festival in 2022
The Guardian: Is Theresa May’s plan for a festival of Brexit just an appalling sop to the DUP?
Do any announcements or statements by the UK government mention the festival is Brexit-related?