London Under Midnight — Simon Clark

The graffiti spread through London that summer like wildfire. Its population carried on with life as usual in one of the richest cities on the planet. But beneath the surface there is change. Men and women are going missing without trace. What has the old African preacher seen emerging from undergrowth near the river? Is this the essence of evil encountered long ago? Ben Ashton is an investigative writer. When he's commissioned to find out who is responsible for the Vampyr Sharkz graffiti he thinks his luck has changed for the better. Little does he guess how wrong he is?