Talking of idiots in Westminster - and I definitely reject the 'safely' comment - here is the latest demonstration they haven't a clue that I have come across:

Most firms that export only to the EU do not have the paperwork they need to carry on their business after a no-deal Brexit, government figures suggest.

The Liberal Democrats said the statistics showed that no deal, which increasingly seems to be the outcome ministers think is most likely, would be a “wholly irresponsible political choice”.

But their analysis was disputed by the government, which claimed that, even though only a minority of firms have already acquired the right documentation, these are the firms responsible for the bulk of exports to the EU.
It is hard to know where to start with that government response. So I will just stick to pointing out that bulk of exports and significance of an export are different things. Being unable to import or export a key security item may have effects well beyond a shortage of Mars bars (to use Boris's example.)