All anglers are obsessive, but carp fishers are the most single-minded of all. They think nothing of spending weeks on the banks of a muddy lake or gravel pit, lines and breath baited, waiting for a bite. Ask an aficionado what motivates him and he’ll speak — with an intensity that sounds a lot like love — about the carp’s unrivalled cunning and fighting ability: its coquettish, crafty takes and its long, blistering runs.