Fox took over the role of chief executive in July 2009, having been hired in 2008 as director of policy and comms.
A seasoned PR professional, he previously was director of corporate relations for Tate & Lyle and director of group comms at technology firm Smiths Group.
Fox’s next move has not been announced but Lib Dem insiders suggested he would look to take up a senior corporate PR role.
‘With his background in blue-chip corporate communications he would be a major catch for any private company,’ said one Lib Dem source.
Hanover director James Gurling, chair of the party’s campaigns and communications committee backed this sentiment, adding: ‘As chair of the CCC its been my privilege to work with him as he has first reorganised the party staffing structure when we lost the short money on going into Government, appointed the party’s first ever director of marketing and made it possible to update our campaigning database.’
In a statement, Fox said: ‘It has been an enormous privilege and pleasure to serve the party as chief executive since July 2009 and as director of policy and communications prior to that.
‘Stepping down from this role is one of the most difficult decisions of my life, but on a personal level I feel that now is the right time to move on.
‘There is no good time for changes like this, but one thing is clear: we need whoever is in place as chief executive at the beginning of 2012 to be in the job until 2015 at least – through to the next general election and beyond.’
PRWeek broke the news on Twitter. It was subsequently confirmed by the Lib Dems and reported by the Lib Dem Voice website with quotes from party president Tim Farron and leader Nick Clegg.
Clegg said: ‘Chris has led the party machine through a general election, our transition to government and through some major organisational and financial challenges. His achievements cannot be overstated and I am personally very grateful to him for his fantastic service to the party.
‘Chris has been a good friend and a major figure in the party for many years and I know that he will be sorely missed at every level of the party.’
Farron said: ‘During his years as chief executive, Chris has led a process of root and branch modernisation of the party organisation, improving systems, process, transparency and efficiency into every area of our operations.
‘He has restructured several key functions, including our policy, communications, campaigns and marketing teams.
‘He has transformed party fundraising, allowing us to raise record amounts for the last election. He has championed the introduction of new election software and recruited and nurtured a very strong central team.’