Dean managed a range of funds for the group, including the £2.1bn UK Opportunities fund and the UK Growth investment trust.

Whitechurch Securities said that it planned to sell clients’ positions in the Schroder UK Opportunities fund following the news.

Ben Willis, head of research at the group, said the manager’s departure added to the list of other concerns about the mandate, including its size.

“Following the announcement of fund manager Julie Dean leaving this morning, we have chosen to sell this fund,” he said. “We had become concerned recently over the size of the mandate and as Dean has been responsible for the long-term performance, having managed the fund since 2002, her departure has made our decision for us.”

Investors also voted with their feet on the UK Growth investment trust, that Dean had inherited following the departure of Richard Buxton. Having traded on a discount to NAV of 5% at the close of play on Friday, the gap widened to a closing level of 8.5% as of Tuesday evening as investors sold out, according to Winterflood Securities.

Jackie Beard, director of closed-end fund research, Morningstar UK, said: “We have placed the Morningstar Analyst Rating for the Schroder UK Growth fund Under Review following the announcement that manager Julie Dean has left the firm. The fund previously held a Silver rating. Matt Hudson, a core member of the Schroder Business Cycle Investment team, has assumed responsibility for the team. However, the board has announced that while the team will take over for the time being, they will make another announcement in due course on the fund’s management, after consulting with shareholders. We await clarity on this and until such time the rating is under review.”

However, not everyone is negative on the change. John Monaghan, Senior Investment Research Analyst, Square Mile Investment Consulting and Research, has kept the group’s rating on the Schroders UK Absolute Target Return fund, another one of Dean’s funds.

He says: “Together with Steve Cordell, she has co-managed the Schroders UK Absolute Target Return fund since June 2011. Mr Cordell will now take on sole responsibility. He is a key member of Schroders’ Business Cycle team and has been investing in this style for over 15 years. We do not feel that Ms Dean’s departure will adversely affect the fund’s management and therefore have not suspended the A rating.”