Improved investment performance drove profits at Henderson Global Investors up by almost a third to £60.5m (€89m) in the first half, but the listed UK asset manager warned recent market volatility could impact fund flows in the last six months of the year.

A 31% rise in profits enabled Henderson to pledge to return £250m to shareholders by October 29, in the form of share consolidation and special dividend. Henderson raised £175m in debt earlier this year, its first issuance, and said this had "delivered greater balance sheet efficiency".