Thompson (pictured) joined Weber more than 11 years ago, initially as deputy consumer MD.
The consumer practice has reportedly tripled in size since she became MD of the division in 2013, winning major accounts including Virgin Atlantic, Burger King, Unilever, Kellogg's, British Gas, HSBC, Pearson and Netflix.
Thompson has held the role of UK consumer marketing chair for a little over a year, leading a team of more than 100 people across the London, Manchester, Scotland and Northern Ireland offices.
She moved to the role in the aftermath of a restructure at Weber Shanwick’s UK operations following the departure of long-standing UK and EMEA CEO Colin Byrne.
Thompson told PRWeek: "After eleven amazing years at Weber, most of which I have led the consumer practice, I have decided the time is right to seek a new challenge and take a new direction in my career. Having built, grown and transformed the practice it is such a hard decision to leave it, but I think I have achieved everything that I wanted to at Weber Shandwick and now having made the decision I am excited about taking a new path.
"What that path is I haven’t yet decided, I think there are exhilarating times ahead for our industry so I haven’t ruled anything out completely but I'm not rushing into anything either."
Thompson's official leave date is at the end of April but she is on gardening leave until then.
Her previous roles include divisional director at Trimedia (now Grayling) and senior account manager at Cohn & Wolfe.