Police/legal procedures

[Twilkes]

I'm writing a piece of fiction, and want to make sure I get the police procedure correct.

If someone is arrested, once they are taken into the interview room, are there any formalities before the interview begins?

Do police still use cassette recorders to record interviews? Or have any gone digital?

If an interview is recorded, is the interviewee asked to state their name for the tape? (were they ever?)

If the first thing an interviewee says is 'Yes I did it, I'll write a statement to say I did it, and I'll plead guilty if you take it to court', would the interview stop there and then? How would the interview be concluded and the recording stopped?

And finally (and I stress that this is for a piece of fiction) if I intentionally attacked someone by hitting them on the back of the head with a pottery bowl, knocking them out, and then pleaded guilty, would I be likely to be out of prison in two years? If it would be more or less than two years, how would I have to alter the crime to make sure it was around two years?

[Twilkes]

Boy, that escalated quickly.

Maybe what I'll do, once I've got the scene written, is post a redux of it and let you pick it apart.

Thank you for DJB's detailed answer, and to the Scots for pointing out that things are different there, as it could well end up in an episode of Balamory.