We have a hire car say, Wednesday until Saturday noon under my own insurance. The car is delivered to my home address but the hire company don't come to collect until Monday morning. They say leave the keys in a safe place if i'm not there.

Come Monday morning:
Scenario 1) The car has been stolen by someone using the keys.
Scenario 2) The car has been damaged although we know it was fine on Saturday night.

Who is responsible in each of these events? Me the hirer? or the Hire company?

Over to you guys

The only safe way to answer this to ask your insurer...

I would say that once your Contracted period of hire has expired, and you have followed all instructions as requested by the rental Company which they consider meets their due diligence responsibilities such as the agreed location to leave the keys(hopefully you would be insisting on a written instruction rather than a unprovable telephone conversation), then its at their risk entirely.

However, I cant see a hire company asking you to leave the keys on top of a wheel if you are living in Toxteth!!!!!!

I think Barnacle has it- and regardless of what the hypothetical staff member says I would also check the terms of the hypothetical contract

I always get a physical check and written acceptance for the return of the hire car, what your hypothetical scenario clears the way for is a 'damage fee' winging it's way to you. Forums are full of punters being stuffed for false damage.

http://www.thisismoney.co.uk/money/holidays/article-4708510/How-fight-against-car-hire-traps.html

Tried it on with me even after a physical acceptance at Geneva Airport. Had photos on my mobile to prove the damage was on it and marked on the hire documents at pick-up.