But that's a distinction only valid in American circles. Here in Europe "modern liberalism" is just the modern development, by modern authors and scholars, of the classic theory and praxis of classic liberalism. So in fact it's the same thing. The Economist is liberal, The Guardian is leftist.
Not so. Perhaps the only noteworthy difference between American and European liberals is the level of forthrightness: In Italy, for example, many liberals nonchalantly refer to themselves as socialists, whereas Americans abhor the term liberal, much less socialist, and have adopted in place of both the euphemism "progressive".
The United Kingdom is perhaps, in some ways, more politically correct than the United States -- demographic projections of a growing Muslim population are evidence of this. Although it should be said, the United Kingdom remains the most conservative in Europe in economic terms.