Sir John Major has said he believes Britain will rejoin the EU or form a “new alliance” with the bloc within the next generation.
The former prime minister challenged Boris Johnson’s decision to prorogue Parliament in September, arguing it was motivated by political interest to push Brexit through without debate by MPs.
After a three-day hearing at the Supreme Court, 11 justices unanimously ruled Mr Johnson’s prorogation to be unlawful.
Young people have been let down
Speaking at the One Young World global forum for young leaders, Sir John, 76, said:
“Young people have been let down, they overwhelmingly wished to remain in the EU, whereas many of their elders did not.
“I have been a critic of Brexit, and I remain so. I think it’s bad for the UK, bad for the EU and bad for Europe, and a colossal mistake. Other than that, I have no complaints about it.”
He added: “Young people prefer cooperation to separation.
“Even the most powerful nations in the world require allies.
“In the end, the young are going to win because they will be here and the elderly won’t.
“One day, I confidently predict, the young ones will reenter the EU or form a new alliance with them.
“Who knows what lies ahead, but it certainly won’t be conventional and it certainly won’t be dull.”
Sir John served as prime minister from 1990 to 1997, succeeding Margaret Thatcher.
He presented the Politician of the Year award at One Young World on Wednesday, which recognises the five most promising politicians aged under 35.
This year’s winners were Venezuelan politician Juan Guaido, South African politician Mbali Ntuli, Icelandic Minister of Tourism Thordis Gylfadottir, French politician and economist Herve Berville and Green MEP for Yorkshire and the Humber Magid Magid.
Related: Ken Loach accuses Labour MPs of trying to undermine Jeremy Corbyn