Will Walden is Boris Johnson’s former chief adviser. He was his director of communications at City Hall and he ran the former London mayor’s transition team at the Foreign Office. However, Downing Street controversially blocked Johnson from appointing Walden as his chief of staff at the Foreign Office. 
Walden is also an ex-BBC journalist.
Walden was appointed by Edelman in December 2016 as its managing director for public affairs.
In a statement, Walden said: 'Edelman represents the best of public affairs with a portfolio that’s benefitted immensely from [his predecessor, Brar Gurpreet]’s leadership. I want to build on that success, driving public affairs integration within the company’s wider UK, European and International operations, while helping to shape Edelman’s growth in what are unique and challenging times politically. [...] I can’t wait to get stuck in - working with an immensely talented and innovative team, building on their ideas and - I hope - bringing my own perspective from media and government to their work.'
Edelman UK chief executive Ed Williams said: 'A respected political strategist, Will has led a team of 75 people and overseen a £10m annual budget during Boris Johnson’s final term as Mayor, alongside having two decades of political broadcasting under his belt.' 
- David Singleton, Edelman wheels in Walden, Public Affairs News, 14 December 2016, Accessed 16 December 2016.