The murder of a child distresses us more than any other crime. Despite the national anxiety created by murderous paedophiles, the crime is mercifully rare: on average only seven cases a year occur in Britain. But a long and difficult hunt can build enormous tension. It did when Raymond Morris killed two little girls in Cannock Chase. Women do sometimes kill children, however. Neighbour's exasperatingly cheeky kids can drive tired housewives over the tip: Jeannie Donald is the classic case. Mothers sometimes kill their own children, either seeking attention, or (as was allegedly the case with Alice Crimmins) for the freedom to pursue their own love-lives.