
Thomson will leave the company at the end of March. His decision follows a round of editorial redundancies and a series of management changes in the past two months, including David King being promoted to chief executive of Time Out Group.
In the interim, Mark Frith, former editor of celebrity magazine Heat, will take charge as editorial consultant and lead the search for Thomson's full-time replacement.
As the stalwart title at the heart of an international multimedia publishing business, Time Out London is considered integral to the group's success. Last year, the London magazine's average paid-for circulation dropped 9.7% to 61,969 and Model Citizen's consultant Richard Lewis was called in to assess the business.
Thomson has been editor of Time Out London since October 2004, moving from the post of deputy editor of the Observer Sport Monthly.