I am sorry to be so blunt.
My early assumption was that the story had an intriguing ring: London, end of the 70s. A young lady, Philippa, knowing that she had been adopted, sets out to look for her biological parents. Her adoptive parents, with whom she never quite had a close relationship, are unhappy about this choice but nothing can stop Philippa. What she eventually finds out is shocking but, seemingly unperturbed, she sets out to try and establish a contact to learn more about her early childhood. Meanwhile, somebody else is looking into the past and, unbeknownst to anybody, is waiting for the right time to strike out, to quench the thirst of vendetta over the murder of his young daughter years ago.
Although the linguistic is definitely high class, the narrative is just too tediously overly-descriptive, resulting in total failure to engage me fully as a good thriller should do. I often found myself skimming through some parts, trying to get to the core of the chapter. Additionally, none of the main characters, Philippa in primis, were particularly likeable one way or the other, no matter how sad or tragic their backgrounds. This too, contributed to a certain degree of dislike for the whole tale.
I know and respect Mrs. P.D. James' reputation as a writer, but this book just was not for me.