SOUTHEND seafront. Early hours of the morning. At this time the waterfront is scumbag territory. You know the types. The sort of guys who’ve been kicked out of hell on one-way tickets for lowering the tone. Muggers. Drug dealers. Harlots. Sharks.

Well, that is how it’s supposed to be. In reality, there’s no one around at all. Not a halfway decent harlot or mugger in sight. Perhaps they overslept. Wait up, though, what’s this?

Proceeding slowly in an easterly direction down the esplanade is a suspicious-looking van. It pulls into a yard at the water’s edge, the doors open. Sure enough, it’s full of sharks. They swim round in hectic circles in a big plastic tank. And they’re mean boys. White-van sharks.

These are blacktips, from tropical Pacific waters. Man, do they have attitude. It’s bad news for Southend if these guys have come to town.

OK, they’re not lethal enough to make final auditions for a remake of Jaws, but they’re still deadly nibblers.

Along the Indonesian coastline there’s more than one beach bimbo who took a paddle and wished she hadn’t. The word is, you can tell the victims by their foreshortened big toe, the calling card of the blacktip.

What are these fish doing here, though? Southend is a bit way out for an Indonesian shark, even when some bimbo has trodden on its navigation system. Being sharks, they’re probably on the run from the law.

To find out the truth, you have to ask David Knapp. David runs all the shark operations in this neighbourhood. He is curator at Southend Sealife Adventure.

Dave had an unusual Christmas present by most people’s standards. Other people get an iPod or a calendar, Dave got around £50,000 to buy himself some sharks.

The fish are destined to be the key attraction in Sealife Adventure’s new tropical tank, due to open next month.

As a dedicated conservationist and educator, Dave says: “The new tank carries a strong conservation message. We’ve been brought up to think of sharks as bloodthirsty predators. In fact, thanks to unregulated fishing, they are victims. Blacktips in particular are close to being a threatened species.”

Few will disagree with this message. The trouble is, who wants to believe in sharks as harmless, passive victims? It’s like discovering tyrannosaurus rexes were into transcendental meditation.

We want to believe in sharks as bloodthirsty attack machines with an insatiable appetite for people in Speedos. Aquariums like Sealife would be a lot duller without the sense of menace they provide. The blacktips grow to six foot, so they could eat us if they wanted.

Then Dave spoils the effect by pointing out: “More people get killed by toilets or vending machines than by sharks.”

What about the blacktips in the van, though? They are swimming round and round in fast circles. They certainly look pretty confrontational and, whatever David claims, a lot scarier than some Coke machine in an office.

But once again, David spoils the effect. “Probably a sign of stress,” he says. “They’ve had a long journey.”

The previous day, the sharks had been hooked out of their pen in a breeding pond in Holland, stuck in the back of the van, shipped across the North Sea to Harwich by two jokey Dutchmen, and driven south to a Southend street noted for its fish and chip shops. Little wonder if they’re a bit stressed.

David is observing them intently for giveaway signs. Sharks’ body language turns out to be surprisingly nuanced. The particular set of a fin will tell him a lot about a shark’s mood.

Swimming upside down is a sign a shark has got real issues, though the rest of us might have guessed that too.

To avoid extra stress factors, unfamiliar stimuli have to be kept to a minimum. That is why the sharks are being moved at night-time, in the dark.

Still, once the sharks are settled into their new tropical tank, they have a month to settle down before the crowds arrive. After their four-week induction period, the sharks will be given names. Then a great new life beckons.

The blacktips comprise a shark family of one male and two females.

Life on Southend seafront will be a constant round of eating and, hopefully, breeding, at a rate that the natives can only regard with envy.

Southend Sealife Adven-ture will then move into a new role as a supply centre. “We are part of the wider community of aquarists,” says David. “In time, the hope is we can increase numbers and bolster this threatened species.”

First, though, comes the challenging part – moving the already stressed sharks from the van to the new pool. Shark shifting sounds like a pretty specialised trade. “The trick is to keep it simple,” advises David.

Using a long net, David gently scoops the first of the blacktips from the tank in the van. It thrashes briefly in the net, as David deposits it in a smaller tank.

Four of us take hold of the tank and carry it through a dark yard. The process needs to be swift but unhurried. We can’t see the fish, but we can feel its uneasy twitches in the small confines of the tank. It is hard right now to see this vulnerable creature as any sort of menace. You feel protective.

At the tropical tank, Lizzie, a keen Scuba diver and ardent conservationist, transfers the first shark to the tropical pool. Sensing freedom, the shark flits off into the darkness.

“He’s a lovely shark,” says Lizzie. “A lovely, lovely boy.”

Disillusioning as it is, you have to agree.