Tim Harford is a 'popular economist' who lives and works out of London. He is probably best known for writing columns for the Financial Times; he writes both Dear Economist and The Undercover Economist; the latter also appears in Commerce (in Canada) and Slate (in the USA). The Undercover Economist is also the title of his first solo book, which has been moderately successful. Aside from this, he also contributes to Forbes.com, NPR's Marketplace, and is the presenter of the TV series Trust Me, I'm an Economist.
Mr. Harford has done plenty of 'real' economic work. He's worked for the World Bank, as a scenario expert for Shell, and as a tutor in economics at Oxford University. He has a Master of Philosophy in economics from Oxford. He is a member of the International Finance Corporation, and is on the editorial board of The Financial Times.
He is an interesting writer who is well worth reading. He specializes in explaining everyday things in economic terms; the price of Starbucks coffee is a favorite subject of his. I have found some of his explanations of everyday economic matters unconvincing. I suspect that he suffers from trying to make one interesting fact explain more than it really can. But this doesn't stop me from reading him -- it just means that I take his hypotheses with a few more grains of salt than I might for other writers. As with most popular science writers, most of his work involves explaining other people's studies in terms that we can all understand, and moreover, be interested in. In this he does an excellent job.