The Nature of the Beast by Frances Fyfield

Amy Petty is dead. But Amy Petty is alive . . . 

Different people react to disasters in different ways. When an intercity service travelling from Kent to London joins Paddington, Hatfield and Selby in a deadly list of notoriety, it isn't only fate that decides who is killed: one passenger uses the opportunity for argument to spill over into murder; while another - blonder, beautiful Amy Petty - sees the train crash as an opportunity to leave her life behind . . .

But why would Amy Petty want the world to presume her dead? It is because of her husband, currently embroiled in a libel action against a national newspaper? Douglas Petty, a former barrister, is rich, charismatic and evil tempered: he runs a dog sanctuary -- inherited from his father -- in his brutally eccentric manner. Amy was to be his star witness: without her, his reputation faces ruin.

Or maybe it isn't the present that Amy is running from. Maybe it is the past from which she cannot escape . . .