Bob Geldof has unleashed a blistering attack on the European Union - saying it does not work.
One of the highest-profile celebrity pro-EU campaigners during the Brexit referendum, he said Brussels needs a radical overhaul quickly.
Speaking before an audience of students in Dublin, Geldof also predicted a European war within a generation or two as the west lurches towards nationalism and populism.
"Europe needs reform - it is sclerotic," he told Trinity College Dublin's Law Society, which awarded him its Praeses Elit medal for his contribution to music and the greater good.
"The whole system is constipated. It needs a laxative to clear it out."
Geldof said half of Europe is desperately unhappy.
"It doesn't function," he said.
"It is ignoring the wishes of European citizens. What worked for six [member states] doesn't work for 28."
One of the most outlandish stunts of the in/out referendum campaign was the clash of Geldof and Ukip leader Nigel Farage aboard flotillas on the Thames.
But the Irish rocker, who was knighted by Queen Elizabeth, said he met his arch-opponent and key Leave campaigner Mr Farage earlier this week at a party and shook his hand.
"He is an immensely dedicated populist. You have to hand it to the guy," he said.
However, he insisted Brexit remains part and parcel of a reactionary movement galvanising the planet that is "really, really dangerous".
"England - that place that represented openness and tolerance, when I couldn't find it here [in Ireland] seems to be closing down," he said.
"It is increasingly less comfortable for me, and others who think like me, being there."
The UK was resiling from the 21st century, he said.
Geldof said the countries in the west are being reduced to economically competing states - and in that scenario countries "go to war at a scratch".
"I think we will go to war - possibly within a generation, possibly two. I really think that," he said.
A "thuggish, predatory Russia being led by a brute" was already invading Europe as we speak, he added.
The poverty campaigner urged students to stop venting their spleen on social media - which he said was "just cyber-w******g" - and get involved in protest and activism.
Asked about criticism of the lyrics of his Do They Know It's Christmas song - one of the best-selling of all time - he said: "My response is I don't give a f***," adding it has so far raised a couple of million pounds for Africa.
