Former home secretary Alan Johnson has said that it's necessary to cede some sovereignty in order to gain from the European Union.
Speaking during a debate on the BBC, Johnson said: "We have agreed that in exchange for this big market that our companies can sell into - a bigger commercial market than the US or china, there has to be rules to govern that, in our interests as well. These rules, we have ceded rules by treaty, agreed by our parliament."
But leader of the commons Chris Grayling, one of six ministers who has gone against the government's official remain position, accepted that while big issues such as tax, schooling, and the minimum wage are controlled by the UK, too many issues are not.
"But it's also the very big issues. Our population is going to rise to 75m-80m and I don't believe we can cope with that. But we cannot set limits on the number of people who come and live in the UK. I think that's the sort of decision that should be taken by our parliament," Grayling said.
Yet Johnson maintained that the UK agreed - in a referendum in 1975 - that competition law should be European wide, so British companies don't suffer from uncompetitive practices elsewhere.
The debate comes after Mayor of London Boris Johnson announced he would back Brexit, primarily on the issue of sovereignty, today asking the Prime Minister to explain to the House of Commons "in exactly what way" his deal returns sovereignty "in any field" to the UK.
The Prime Minister said it brings back powers on welfare, immigration and bailouts, as well as leaving the UK out of the ever-closer union.