Google has appointed Eileen Naughton as managing director of its £3.6 billion per year UK advertising sales operation.
Naughton has been with Google since 2006 and previously was president of Time Magazine.
The global sales executive, currently based with Google in New York, will replace Dan Cobley, who has been UK MD since October 2011.
Commenting on the move, he said: "After more than a two and a half years leading Google in the UK, I'm looking forward to the challenge of leading Google's growing brand business in Europe, the Middle East and Africa, helping businesses market their brands online."
The announcement comes shortly after Google gave Thomas Davies, the head of its UK Enterprise business, a wider remit that involves him overseeing the internet giant's business offering with companies across Northern, Eastern and Central Europe.
The UK is Google's largest market outside the US, accounting for $5.6 billion in revenues in 2013, or a tenth of its global sales. That was a 16 per cent increase on the previous year but still its slowest growth rate for three years.
Elsewhere, Japanese technology giant Fujitsu appointed a new chief for its £1.8 billion UK and Ireland business.
Michael Keegan will replace Duncan Tait who was promoted in March to head of Europe, the Middle East, India and Africa.
Keegan has spent the last three and a half years leading Fujitsu's Technology Products Group for the UK and Ireland.
Sign up for CIO Asia eNewsletters.