Large glasses of wine??

Went in to my local at lunchtime, King's Head in Roupell Street. Asked for a large glass of Picpoul as usual and told. very politely, we don't do large glasses now because of Brexit.
On questioning the answer varied to, because the wine comes from abroad

The management of the King's Head are entirely within their rights to alter the size of glasses they serve, what they are not entitled to do is to blame it on extraneous issues. Brexit is not an issue, since it hasn't happened,and there is nothing in current plans which would alter glass sizes. They also sell South African wine, again Brexit cannot be involved. So what is going on. It speaks of a total lack of integrity form an otherwise excellent establishment.

How very weird.

As much as I appreciate blaming Brexit for bringing nothing but misery, I don't really get this.

You're right that that doesn't make sense....

We haven’t left yet!

A standard glass of wine contains 175ml of liquid, a large glass 250ml.

Not offering for sale wine a large glass does not constitute an alteration of size: it is merely a reflection of the business model of that establishment.

The amounts of grams of alcohol in the wine glass is just as important as the size of the glass. I am right in thinking that the UK allows a maximum of 8gm per unit, whereas everywhere else in the EC offers at least 10gm which is 25% more than the UK?

Talked to them again yesterday and got the much more sensible answer that it is part of Drinkaware and responsible drinking. Good for them, they just need to let all the bar staff know the reason.