The former Daily Mirror political editor will remain at the FCO on ‘project work’, with the post covered by deputy director Simon Shercliff in the interim.
‘Six years is, as far as I understand, a record for anyone staying in this post – it has been six years of incredible intensity,’ Williams told PRWeek.
The announcement of his departure comes less than three months after that of deputy communications director Peter Reid (PRWeek, 31 March).
Williams, the first non-civil servant to be appointed to the top comms role at the FCO, described the timing of the exits as purely ‘coincidence’.
The postholder reports to the Foreign Secretary, Margaret Beckett.
The FCO is also recruiting for a replacement for head of media events Pat Barrie, who is staying within the FCO but leaving the comms team.