IDP is a legal requirement in the Philippines. It is the Philippines which pass on the required driving details to the UK government, who then gives it to the Post Office, AA, etc.

The car hire company are not responsible for you having incorrect paperwork, YOU ARE. Your license could be a fake, they are not responsible if it is, the person with it is.

That I would think is VERY CLEAR INFORMATION.

Yes you can drive for 90 days in someone else's car as long as the insurance terms allow it. Yes you can probably hire a care without one. However, you are still responsible for having one.

http://www.rac.co.uk/travel/driving-...ed-an-idp.aspx
https://www.car-hire-centre.co.uk/in...ng-permit.html
http://www.driverabroad.com/self-dri...riving-permit/
http://en.wikipedia.org/wiki/Interna...Driving_Permit
http://www.driveaway.com.au/internat...driving-permit
http://www.worldlawdirect.com/articl...s-license.html
http://www.europcar.com/EBE/module/r...riving-permits