Corruption of one sort or another has always appeared to fascinate Caroline Blackwood but this is the first of her five novels to really get to grips with it. In Corrigan, she tries to analyse not just the meaning but the effects of corruption and comes to some surprising conclusions. ‘I’m so interested in Corrigan’, one character in the novel says; ‘I’m so interested by his intense high mindedness. I’ve noticed that high moral fervour often seems to go hand in hand with extreme corruption.’ And that states precisely the author’s theme.

It is a theme Caroline Blackwood develops in an uncharacteristically ponderous fashion. First we meet Mrs Blunt, an attractive elderly lady recently widowed who is living in a state of suspended animation in her period residence somewhere in Wiltshire. Her marriage to the dead colonel was so blissfully happy, and her grateful dependence on him so total, that grief at his sudden demise has paralysed her. If it was not for her boisterously devoted treasure, Mrs Murphy, she would hardly know she was alive herself. Mrs Blunt’s helplessness, her palpable despair, enrages her only child, Nadine, and not least because Nadine cannot but contrast her own unsatisfactory marriage, from which she would gladly be released, with her mother’s shattered idyll.

Into this static household of Mrs Blunt’s comes a crippled gentleman, one Corrigan. He wheels himself to Mrs Blunt’s door and is carried into her astonished presence by the redoubtable Mrs Murphy, crudely yelling that there’s a cripple to see her. Corrigan, handsome and impressive in spite of his useless legs, is collecting money for St Crispins, the hospital where he himself has been wonderfully treated.

At first Mrs Blunt is appalled at being so brazenly accosted, but gradually she warms to her extraordinary visitor. She admires him and contrasts her own apathy with his courageous initiative. Ready to make a generous donation she is amazed when Corrigan asks her instead to write to a Rupert Sinclair, inmate at St Crispins, who badly needs a friend. And with that masterstroke he bowls off along the country lanes.

Now Caroline Blackwood is too skilled for it to be an accident that several things are at once obvious so early in this novel: it is obvious Corrigan is a fraud, obvious Rupert Sinclair is himself, obvious that nobody is going to swallow all this for long. This being so, what can be Caroline Blackwood’s purpose? It seems that she is going to rely for interest on the exposure of the fraud and on the confrontation between Good and Evil.

Never before has there been anything in the least clumsy about Caroline Blackwood’s style – one remembers in particular the subtlety and elegance of Great Granny Webster – but suddenly and alarmingly there is. Although the plot is hardly the chief attraction of this novel the unravelling of it is agonisingly meticulous. Corrigan, the pivot upon which such action as there is turns, remains elusive. As Mrs Blunt falls more and more under his spell – to the extent of altering her house to suit the needs of the disabled – Corrigan becomes more and more unconvincing. A child of two could see through him. Ah, but that is part of the plot: of course Mrs Blunt sees through him, but the point is (and it is to become the point of the novel) she doesn’t care. Corrigan, crook though he is, has given a purpose to Mrs Blunt’s wrecked life. She enjoys using her gardening and artistic skills to raise money for him. It is absolutely irrelevant that he is cheating her because activity has made her happy. And evil though Corrigan is, she knows him to have been touched and changed by her own kindness. She has had an effect on him which he is powerless to reject.

Mrs Blunt dies, the hows and whys of which event provide Caroline Blackwood with more chances to elaborate in the solemn way of earnest detective story writers. But at least the pace then quick-ens. Nadine, lacerated with guilt, is determined to hound the wicked Corrigan (who has disappeared after the funeral). She tracks down St Crispins only to discover it is a seedy Pancake House – and suddenly, if briefly, Caroline Blackwood is back on form describing this awful place and its inhabitants with her customary humorous energy. With considerable verve she follows Nadine through the tortuous path her reasoning takes before she decides Corrigan may not have done the harm she had supposed. Phew. We are there at last.

Some novelists can use ‘themes’ as scaffolding and erect splendid constructions with their help so that in the end they are invisible. Caroline Blackwood has failed to do that. Moral philosophy proves not to be her strong point, not on this scale. She debates and equivocates and speculates and the result is that her writing becomes forced and anxious. Corrigan is a contrived performance, lacking the hypnotic power of much of this immensely talented novelist’s earlier work.