Baillie Gifford has replaced the management of its £900million Monks global investment trust with another in-house team.

It says the trust will move from Gerald Smith, former chief investment officer at the Edinburgh-based partnership, to the Global Alpha desk. Run by Charles Plowden, one of the firm's two joint senior partners, the desk manages around £20billion for mostly institutional clients from around the world.

James Ferguson, the trust's chairman, said: "It is now appropriate that changes are made at the portfolio management level in order to improve performance. Baillie Gifford's Global Alpha strategy..... has a well established process and a strong performance record."

Monks is the only large-scale trust in the global growth sector with a discount as wide as that of Alliance Trust, currently under attack from an activist campaign aimed at reducing that discount.

While shares in Baillie Gifford's top-performing trust in the sector Scottish Mortgage have been trading at a premium to asset value, Monks was at a 14.2 per cent discount yesterday (Alliance was at 13.7 per cent).

Analyst Alan Brierley at Canaccord Genuity said the average discount in the sector was around 5per cent.

Mr Brierley said Monks under its current strategy since 2005 had outperformed the world index in eight years out of ten. "Although we have a high regard for Gerald Smith, Monks had clearly lost momentum and the time had come for a change."

On Mr Plowden's team, he said: "The style is proven while we are impressed with the clarity of investment philosophy and process, and the £20bn of assets under management is evidence of the strategy's success."