I assume you're talking about the Chartist movement, which is not considered a civil war. 1848 was, however, the so-called "year of revolutions" across Europe. England managed to avoid most of it. From the article cited:
Elsewhere in Britain, the middle classes had been pacified by general enfranchisement in theReform Act 1832; the consequent agitations, violence, and petitions of the Chartist movementcame to a head with their peaceful petition to Parliament of 1848. The repeal in 1846 of the protectionist agricultural tariffs – called the "Corn Laws" – had defused some proletarian fervour.
On a completely separate note, it just occurred to me that the title of this thread could be taken to mean something VERY different depending on how you read it. Heh.