Sadly, he was probably being literally sarcastic.
Nottingham has gained something of a reputation in the last few years and statistically is rated as the city with the biggest gun crime in the UK. At one point, IIRC, it's police chief was hauled over the coals for saying that the city was completely out of control and the police couldn't cope with the murder rate. But that was a couple of years back.
Whether the stats mean much, of course, is debatable. It's probably like most big cities - be careful, watch where you wander, and you're probably as safe there as anywhere else these days.
LabRat