By Jessica Frank-Keyes The UK’s level of economic inactivity due to sickness could reach 4.3m by the end of this parliament, with an “unthinkable human and economic cost”, a health report has warned. A cross-party commission on health and prosperity, led by the Institute for Public Policy Research (IPPR), has published its findings on the future of Britain’s health policy. Experts including Greater Manchester mayor Andy Burnham and former Tory health minister Lord James Bethell found the UK’s health crisis is linked to our faltering economy. It comes just days after Lord Ara Darzi – who co-led…