BRITAIN will lose about £600 million in tax each year due to a US exemption from a landmark international tax commitment, the public accounts committee (PAC) said today. It confirmed HMRC estimates that exempting large US multinationals from the minimum effective corporate tax rate of 15 per cent would reduce Britain’s take to £1.6 billion. The PAC also warned there are still “significantly high” risks with HMRC’s approach to multinationals diverting profits across borders.