One of the driving forces behind supermarket chain Morrisons’ recovery from its controversial Safeway acquisition is to leave the business.

Finance director Richard Pennycook, who joined the Bradford-based company in October, 2005, is seen as a “safe pair of hands” by City analysts, with one describing his departure as an “unexpected disappointment”.

Shares fell two per cent on the announcement, wiping more than £120 million from its value and adding to pressure on the chain after recent figures suggested its market share was being eroded amid challenging trading conditions.

Mr Pennycook, who will leave by next June, was appointed after the chain recorded the first loss in its history on the back of its £3 billion acquisition of Safeway, which transformed it into the UK’s fourth biggest grocer.

Its shares have risen more than 50 per cent since then, with profits hitting £947 million as Mr Pennycook has been widely viewed as a key part of its success, taking on broad responsibilities for finance, IT and strategy.

Independent retail analyst Nick Bubb described the announcement as a shock: “The news about his leaving comes at an awkward time for the business, with trading under pressure as Tesco fights back.”

The acquisition of Safeway led to a difficult few years for Morrisons as it struggled to integrate the new business, which increased its presence in the South of England.

But Mr Pennycook played a central role in the ‘optimisation plans’, which eventually overcame the problems.

Morrisons’ chairman Sir Ian Gibson said: “Richard has done an outstanding job over the last seven years.

“He was the architect of the company's optimisation plans and has played an increasing strategic role in the last few years as Morrisons has completed its transformation into a nationwide retailer.”

But more recently trading has slowed, with the latest data from Kantar Worldpanel showing that the chain’s market share dipped in the 12 weeks to June 10.

Mr Pennycook said he planned to seek new challenges with a ‘portfolio career’ in numerous roles.

Clive Black, an analyst at Shore Capital, said: “He is considered by considerable elements of the market, in our view, to be a safe pair of hands, having brought much needed control and stability to Morrisons after a period of turmoil post the Safeway acquisition.

“Morrisons will not sell any fewer baked beans because its finance director is going.

“However, his departure is an unwelcome loss and distraction for the board.”

He was seen as a potential candidate to take over as chief executive when Marc Bolland left to lead Marks & Spencer, but the role was given to Dalton Philips from Canadian retailer Loblaw.