LONDON (Reuters) – Britain’s competition watchdog has been asked by the government to review the retail fuel market to see whether a cut in duty has been passed onto consumers as prices at the pump hit unprecedented highs. Business Secretary Kwasi Kwarteng said on Sunday the investigation would find out why fuel prices were always quick to rise but slow to come down. The price of oil has surged worldwide, driven by Russia’s invasion of Ukraine and economies reopening after the pandemic. Britain reduced fuel duty by 5 pence per litre for one year in March in a 5 billion pound ($6.2 billion) pac…