Charles Dickens’ childhood was overshadowed by the improvidence of his father, John,and the chaotic state of the family’s finances. At 11, Charles, was sent to work in a boot-blacking factory. A little later, John Dickens was taken to the Marshalsea, the debtors’ prison. His wife and their younger children moved in with him.

In the semi-autobiographical David Copperfield, Dickens relived the sense of shame, bitterness and dashed aspiration that he experienced at that time. Six years later, in Little Dorrit, he returned to that traumatic experience, setting much of the novel in and around the Marshalsea itself.

I first encountered Little Dorrit as an A-level set text. It’s a long novel. The sprawling plot and enormous cast of characters can be daunting at first. It’s well worth persevering.

My one-phrase summary is that Little Dorrit is a book about prisons.  Some are physical, like the Marshalsea or the prison cell in Marseille where the novel opens. But characters are also imprisoned by psychological walls or by social mores and expectations from which they cannot break free.

Little Dorrit is a darker novel than the early books like Nicholas Nickleby or David Copperfield. The exuberance of language characteristic of Dickens is here, but also a more subtle approach to characterisation. We see William Dorrit, father of the eponymous heroine and whose character was based on John Dickens, clinging to a contrived sense of status as Father of the Marshalsea. We know that this is self-deception yet feel pity, not contempt.

There’s plenty of humour, from Mrs General and her elocution lessons (“papa, potatoes, poultry, prunes and prisms”) to Flora Finching describing her brief marriage and widowhood (“ere we had yet fully detected the housemaid selling the feathers out of the spare bed Gout flying upward soared with Mr F to another sphere”).

What I love about the book is how comedy and sadness are juxtaposed. Flora is on one level a tragic character, a widow, lonely and lumbered with caring for her late husband’s elderly aunt, who probably has what we now call dementia. Yet it is impossible not to laugh at the language that Dickens gives both of them.

There is humour too in the social criticism. The Circumlocution Office, striving to promote its fundamental approach to government of “how not to do it”, anticipates Sir Humphrey by more than a century. But Dickens’ anger also bursts through the comedy when he writes about the ordinary people whose lives have been wrecked by bureaucratic self-interest or by the corrupt financial speculation of Mr Merdle.

At the end, Dickens vision of what is possible is mature and humane. His hero and heroine can look forward to “a modest life of usefulness”. Dickens reaffirms the transforming impact of human love and commitment but recognises that those virtues have to be lived out in a world where “the noisy and the eager, and the arrogant and the froward and the vain, fretted and chafed and made their usual uproar”.

David Lidington is a Conservative MP and the Leader of the House of Commons.