It's not every Christmas you are invited to jump into a shark tank but I was pretty chuffed to get my ticket to the Shark Awareness course at Blue Planet Aquarium in Ellesmere Port, Cheshire. It promised a whole day of lectures about sharks and then to top it off, a dive into the tank with the specimens, including sand tiger sharks, lemon shark and nurse sharks.

Being an amateur naturalist (okay, that just means I watch a lot of David Attenborough) I was not sure how much the lectures would teach me but I was impressed at the level of detail gone into on the day. We were taught to classify the sharks into different families, the various ways they give birth and how to read some of their body language along with a great deal about shark and marine conservation. There was just no chance of being bored. We got a tour of the facility to see how the fish are all cared for and stood on a metal pathway over the tanks. The shark that you see in the viewing gallery looks pretty big through the glass. That same shark viewed from overhead a few feet away looks massive. Too late to back out now.

It was finally time to kit up and get ready to meet the toothy ones. I was wearing a 5mm longie as recommended but the water was pretty chilly and if you're a wimp like me, I would recommend a shortie over the top as well. You won't be moving much to keep warm. No shot is allowed so solid weights only and you won't need a lot of air so leave the 15l at home. The one piece of kit you won't need at all is your fins; you walk rather than swim.

Into the tank. Arms folded or at your sides in case hungry sharks mistake your waving arm for an offered snack. Smile and wave discreetly to members of your family who are watching you and taking pictures that don't come out very well because of the glare off the glass. The sharks come in close. Really, really close. The sand sharks in particular try to part your hair with those wayward teeth. A large stingray swam past and thought about sitting on a diver's head before moving off somewhere else. Our guides were at the ready to poke the sharks if they looked too inquisitive but the sharks were accustomed to people and just swam by without paying us much interest. The most interactive creature was a triggerfish who likes you to shower him with sand and gives you a little nip when you stop.

We all came out with huge grins on our faces. Okay, so these are fish in captivity but we learnt a lot and I'd much rather dive with these fellas than go cage-diving somewhere where the sharks are lured in by chum so they learn to associate humans with food and are harrassed by boats with tourists to keep happy. It's a great day out and I recommend it.