Paul Myners, the City grandee and former chairman of Marks and Spencer, has weighed into the heated political debate on private equity with a broadside against the sector.

Mr Myners criticised the lack of job security and loss of benefits for the thousands of workers now employed by private equity – which owns businesses employing close to one in six UK private sector workers. He questioned whether pension trustees were looking sufficiently closely at the costs of investing in private equity against public stocks.