The consumer goods giant sold the shares in two blocks – 500,000 on 2 November at 205 pence-per-share and 220,000 yesterday at a price of 208 pence-per-share, netting it £1.48m in total.

On 1 October Unilever sold two million shares for £4m, reducing its stake in the business from 37% to 20%. In April it sold off £500,000 worth of shares, an amount matched by CEO John Kearon, to fund the establishment of an equity-based incentive scheme for employees and managers.

Unilever has been an investor in the research agency since 2003.