Pre-authorisation charge

I know that when you use a contactless card for the first time and every so often after that that a pre-authorisation charge of 10p appears as a transaction.

And this disappears and is replaced by the correct charge within the next day or so which is great.

However, I have noticed that the pre auth charge is now £1
When did it change from being 10p?

Overall, it doesn’t make any difference to your daily travel cost just odd that it’s been 10p for years and now it’s shot up 🙂