...about personal tax and mortgages in the UK (London)

Many greetings and salutations to all, and may I say what a privilege it is to join such an excellent community online.

I have intended to relocate to the UK for quite some time, and have recently received introductions (and generous offers, given my level of professional experience) from multinational corporations for positions based in London.
As a prospective expatriate, I am curious to learn:
- how much taxes should I realistically anticipate to pay, based on an annual income between GBP100K to GBP120K?
- will there (or rather, in what form of) tax deductions, exemptions or savings will be available to me?
- should I choose to purchase property, what sort of mortgages (if any at all) can be made available to me (and what the terms and conditions might be)?
I understand that these enquiries pertain a rather broad subject matter, and would appreciate any views or leads that could point me in the right direction.

Many thanks in advance.

Warmest regards,
REZA