Herridge confirmed the move in a tweet yesterday:
Personal news: 15 years after I started the company that became MWW London, yesterday was my last day. It’s been huge fun but new pastures beckon. Endless thanks to all the fabulous clients and colleagues over the years. pic.twitter.com/DJ4Qp128UR— Patrick Herridge (@PaddyHerridge) January 1, 2019
He told PRWeek: "It’s been 15 years since I started Parys [which was sold to MWW in 2013] and for me it was the right time to move on. I was always going to be [in the UK chairman role] for a limited period and (to leave at the) end of the year was always a neat time."
Herridge said he would be "taking a bit of time out", but would still be involved in Social360, the corporate social media monitoring company that he co-founded, while also looking for other non-executive roles.
He said there was "no acrimony in the departure" and wished all the best to Rebecca Blinston-Jones, who was promoted to UK MD in August.
Blinston-Jones confimed the UK chairman role would not be replaced. She reports directly to founder and CEO Michael Kempner.
Blinston-Jones told PRWeek: "I wish him all the best - I'm sure he'll do amazing things. I'm sure our paths will cross again."
The US-headquartered, independent agency currently has 20 staff in London out of a total of 200 globally. Major UK clients include News UK and Sky Media.