Those in the UK are actually using fuel with similar octane to that which is used in the US. The UK uses the RON octane rating. The US uses the CLC rating which is an average between RON and MON. Therefore, 95 RON (UK) = 91 CLC (US). 91 RON = 87 CLC and 98 RON would be comparable to 93 or 94 CLC.