Bank took put in and took out 3k from my account without notifying me

Hi.
This might seem a silly questions, but I'll fire ahead anyway.
I got a letter in the post recently from my bank saying we took 3k out of your account by mistake. Sorry about that, etc.
I checked my current account and noticed that they put in 3k and then went and took it out a few days later.
I once put money into a colleagues account by mistake and the bank under no circumstances would allow me to take it out. Even though the colleague rang them and told them it was a mistake.
I would have thought the bank should have notified me at least prior to this and if they can do it, then why not allow us to do it too. I have heard cases where money was put into someones bank account and the bank had to request it back absurd that it may seem.

The difference is that they made the mistake, so they have to rectify it asap (assuming there are funds to do so). It was most likily where another customer had put down their correct account number and the bank clerk keyed in the wrong number by accident. So they put it in & take it out straight away & send you a letter just to let you know that the error happened - you're not out of pocket in any way, from what you indicate.

In your case, you made the mistake, therefore the correct account holder must notify them that the funds were lodged in error (I can't see a phone call being sufficent for this)

My understanding is that there is no distinction in law between a mistake made by a bank and a mistake made by a customer if funds are mistakenly credited to a wrong account. The customer whose account has been credited in error must be asked to authorise the contra entry to correct the error. If he refuses, then the bank may seek a court solution.

Trouble is that this principle is not enshrined in any statute which can be quoted, but is well established by precedent.