Blimey! I thought I was bad.

That's strange!

My Little Grey Book of Mysteries (page 64) says 100.0 RON.

Wouldn't want to discourage a Welshamn over 1.0 RON...........................

Came across this in my quest of what you get when you mix ASDA's finest with V Power :-) not sure how accurate the calculator is but it's sure to bring out the mad scientist in some....

http://www.motorsportsracingfuels.com/OctaneCalcul...

Pump Fuel
(a) Petrol: Motor Gasoline of the type on sale to the
general public from UK roadside filling stations
(see Appendix 1):
BS4040 (leaded) subject to possession of a valid
permit for use, LRG (unleaded) in lieu of a BS or
EN standard (TBA), BS EN 228 (unleaded) and
BS7800 (super-unleaded).
Petrol is a product refined from crude oil that
contains a large number of identifiable
compounds that can typically be 250 in number.
These compounds can be identified and
compared to the available petrol from major oil
companies and suppliers.
Unless otherwise stated or the distinction is made
between leaded and unleaded petrol, the motor
gasoline fuel shall meet the following: Acceptance
levels for Octane Numbers will be accepted or
neglected according to the Standard ASTM
D.3244. Only additives to this Motor Gasoline Fuel
solely for the purpose of lead replacement are
allowed. Lead Replacement Gasoline (LRG, also
known as LRP): Lead replacement gasoline (LRG
also known as LRP): Only additives to unleaded
motor gasoline, solely for the purpose of lead
replacement, from Sodium, Phosphorous or
Manganese are allowed, subject to application
according to manufacturer’s instructions and to
the treated fuel complying with (B) Appendix 1.
Lead in excess of EU Directive 98/70 EC
requirements is illegal. This also applies to ‘Free
Fuel’.