for one of the world s biggest tourist markets. as we ve been hearing, the uk will set out its demands for changes to the northern ireland protocol today when the brexit minister, lord frost, makes a speech in lisbon. the protocol, agreed by both sides, prevents a hard border on the island of ireland by keeping northern ireland in the eu s single market for goods. our reality check correspondent chris morris is here. remind us what this is all about. yes, the northern ireland protocol is part of the brexit withdrawal deal, the bit of the deal dealing with northern ireland and it was agreed by both sides in 2019. and what it does, in effect, is set up a series of checks and controls on goods moving between great britain and northern ireland, which has made it a lot more difficult to supply a whole range of things into northern ireland. the reason those controls were agreed is both sides were