Is a Swiss identity card proof enough to be able to purchase alcohol in Scotland?

In reality most places in the UK tend to be quite relaxed about the situation. Some countries like the USA are strict and you will be asked for ID almost every time if you are under 25 or 30 years old. But it does not occur so often in the UK in pubs and clubs (supermarkets are often stricter).

But of course some places will be stricter than others.
(I also used to look young when I was 18 - 20, but in reality was very rarely asked to prove my age!).

But if you are asked to prove your age the issue you are going to face is that the average person serving drinks or allowing admittance to licenced premises has probably never heard of let alone seen a Swiss national identity card. Or any national identity card!

This is because in the UK there are no identity cards issued at all. And all international travel is done with the use of a passport only.

This is why the official advice is a photo driving licence, a passport, or a UK only "proof of age card". As these are accepted and trusted sources, and most people would have experience of them and trust them. And they are difficult for the average under 18 drinker to easily forge.

This is probably where your friend suggested using your Swiss passport. As even if they have never seen one before, most people would feel confident about it proving your identity in comparison to an ID card.

In the UK then it is up to the person serving you to decide if they feel you are old enough or not and if not ask for ID.

So it could be that: - You never get asked on your whole trip - You get asked in some places and they accept your Swiss ID - You get asked in some places and they reject your Swiss ID

So I would suggest that to be safer you could take your passport anyway. They either won't look at or care about the validity. Although, of course the photo has to be recent enough so that it still looks like you!

Or you can risk it. But accept that in some places you might get refused and you need to go somewhere else.

If the picture clearly looks like you and the card has your date of birth in an obvious format like 03/10/1995 (or 1995/10/03 although we are less used to the ISO standard in the UK) then you should be OK. Even 03 Okt 1995 although that may take some explanation. I suggest you say that you only have your Swiss document but it does have the date of birth and point to it. If the date is labelled in any of the official languages of your country you may strike lucky and the server can read that language.

Note by the way that the rule applies to buying alcohol for someone not just your self. I have had one of my lunch companions asked for ID when I tried to buy a bottle of wine for three of us to share. So if you get rejected in the supermarket it is no good turning to the old age pensioner behind you in the queue and asking them to buy it for you.