I'm setting my timezone like so:

ln -sf /usr/share/zoneinfo/Europe/London /etc/localtime

It works fine, I check with date and all is good.

But then a few days later I'll realise it's reset itself to CEST, so 9am becomes 10am, etc.

The server is located in Paris, in the CEST time zone. But I should be able to use any zone I want, surely? I (and most of my users) am based in the UK, so I want to operate on that timezone.

I just did a yum update and noticed it wanted to update tzdata. That had the effect of changing from BST to CEST, but I don't think it's the only thing that triggers the change, as I'm sure it's gone wrong on days where I've done no such update. I could be wrong though.

What's the trick to set a timezone permanently?

Thanks