The longstanding chairman of the UK's biggest pension fund, the Universities Superannuation Scheme, has retired, as the scheme embarks upon what could be its biggest set of changes in years, involving capping academics' generous pensions.

Sir Martin Harris, who is 70 years old, ceased to be a director of Universities Superannuation Scheme Limited on March 31, according to a filing at the UK's Companies House. A spokeswoman for the scheme confirmed he is retiring.