By Kate Holton and Susanna Twidale LONDON (Reuters) – Britons will learn the scale of the financial pain they face on Thursday when the energy regulator Ofgem announces an increase to its price cap, with under-pressure households expected to see bills soaring by about 50%. Ofgem will announce the new cap at 1100 GMT – an hour before the Bank of England is expected to hike interest rates again to tame surging inflation. The cap covers consumers on standard variable energy tariffs, rather than fixed tariffs, equating to around 22 million households, and will come into effect from April following…