Which is different in what way to the current situation?
Apparently, before Brexit, all the Northern states were able to vote for austerity to the detriment of poor little Greece. Afterwards, they'll be able to stick two fingers up to the Northerners and go on a spending spree.
The real problem though is that Greece's monetary policy is determined by Germany by virtue of the Eurozone, something that the UK was never part of. He's kidding himself because he is desperate.