By Alistair Smout, Andrew MacAskill and Elizabeth Piper LONDON (Reuters) -Britain’s new government said on Wednesday it would not reverse its vast tax cuts or reduce public spending as it sought to stand firm in the face of yet more turmoil in financial markets and concerns over its change in economic policy. British financial markets have been under strain since last month when finance minister Kwasi Kwarteng announced 45 billion pounds ($50 billion) of tax cuts and unprecedented support on energy bills without saying how they would be paid for. The Institute of Fiscal Studies think-tank has …