There are desks with computers on them, a photocopier, and a water cooler. Above the sink in the kitchen area, someone has put up a reminder about washing up cups and cutlery.

It looks much like any other office in Bristol. Then Alan Evans raps his knuckles against one of the magnolia-painted walls with a dull thud. "These," he says, "are made of steel."

Such a description might seem more appropriate to a villain's lair in a James Bond film, rather than to a cluttered office in a Bristol side street.

However, this is the headquarters of the South West Illegal Money Lending Team, which was set up to tackle the growing problem of so-called loan sharks.

"Our colleagues in the north of the country were firebombed," says Alan, who heads the team.

"We're under no illusions about the sort of people we're dealing with, which is why our location's a closely guarded secret."

There are bars on the window above the stairs that lead to the office. Above the desks there is a CCTV monitor showing images of entrances to the building.

"We need to know who's coming in," says Alan. "When I started doing this job I didn't realise there'd be so many different facets: criminality, drugs, sex, counterfeit goods. We've opened up a Pandora's Box, and for the loan sharks there's a lot at stake."

The South West Illegal Money Lending Team was launched about a year ago, and had already been responsible for the arrests of 14 suspected loan sharks.

Those who have had an unexpected knock at the door have ranged from a woman in her 70s on a north Bristol housing estate to a 37-year-old man from the Far East living in south Bristol. "It's just the tip of the iceberg," says Alan grimly. "And there are a lot of icebergs out there."

The 10-strong illegal money lending team is led by Bristol City Council's Trading Standards Department, but operates through the South West from Gloucestershire in the north down to Cornwall in the south.

Already their workload has increased so dramatically that the specially reinforced office has become too small, and staff will soon be moving out to another secure building.

"It's a problem that's getting worse because of the credit crunch. Our call rate has increased dramatically – gone up ten-fold – even in our short existence," says Alan.

"We're coming across more and more victims of loan sharks who aren't the typical low earners they usually target. They're driving around in Jags and Bentleys but are struggling financially and can't get any help from the banks.

"It's a new type of victim that we wouldn't have seen a year or so back."

The illegal money lending team's new premises will be shared with police officers. "Because of our work with other law enforcement agencies we've been invited to join them in the same building, which is the first time this has happened anywhere in Britain. This will enable us to better share our resources," says Alan.

"Loan sharks have an impact throughout communities that go beyond the individuals directly involved. If you can imagine a spider's web, the loan shark like a spider sitting in the middle of it all.

"If you take a loan shark out of the community, the crime rate is reduced in the area. A lot of people resort to burglaries and muggings to service their debts to a loan shark."

There are some plastic sharks on Alan's desk, together with some shark-shaped keyrings, all bearing the distinctive 0300 1234 247 hotline number for people having problems with loan sharks.

The little toy sharks look quite appealing. In real life, Alan observes, loan sharks can be very unpleasant – although they are often charming to begin with.

"These individuals are everyone's friend until someone can't pay them back. Then things get very nasty.

"We've come across guys who've had guns put into their mouths, and who've been attacked with machetes and baseball bats.

"I was on the phone the other day to a man who had a loan shark after him. The loan shark rang on the other line, and the guy held it to the phone so I could hear him threatening what he was going to do to the man's wife and to his kids.

"Loan sharks will follow people who owe them money for years. If they say they're going to get you, then they will."

Why would anyone want to get involved with a loan shark?

Alan begins to explain. And as he does, he provides an insight into a hidden world of people on low incomes who cannot get credit from high street banks, and end up turning to loan sharks.

"Loan sharks prey on those most in need of money," he says. "It's a sub-culture, and it's frightening how people are led into dependency.

"Sometimes it goes through generations of a family. Sometimes people have the wrong postcode, a bad credit history or no credit history, and they find it difficult to get a loan.

"The majority of people who obtain money from loan sharks are on low incomes. These are people who are mostly on benefits and living in social housing, and when you go into their homes there are 42in flat-screen TVs in their bedrooms and their kids' bedrooms.

"Getting money from a loan shark seems an easy option for people on low incomes who want luxury goods, or parents whose children are demanding items like X-boxes and flat-screen TVs."

The easy money from loan sharks can come at a very high price – in more ways than one.

First, there are the interest rates, which appear to be arbitrarily set upon the whim of loan sharks.

"We've had people paying interest rates of 500 per cent. There was even one which we worked out was 8.4 million per cent," says Alan.

"You ask people how much they owe a loan shark and they don't know. The loans keep getting topped up, and they don't understand about interest rates and annual percentage rates."

Then there are the problems that arise when people find themselves unable to pay back the money – and exorbitant interest payments – that they owe a loan shark.

Alan explains: "Once you get involved with a loan shark, it absorbs you into a criminal lifestyle. It's a bit like drugs – you become dependent, and you get in deeper and deeper.

"The loan shark often gets the money they're owed by issuing threats. But sometimes they get people who owe them money to do things for them. They're so deep into debt that they've got no prospect of paying it back, so the loan shark gets control over their lives, and their families' lives.

"Some people become sex workers, or go out stealing, or get involved in the drugs trade, or act as money launderers to facilitate the movement of cash for the loan shark.

"Others end up getting their benefits paid direct to the loan shark, who starts giving them pocket money."

Illegal money lending teams such as the one covering the South West were set up by the Government in response to crimes resulting from the activities of loan sharks.

"Before the teams were set up, the police could deal with a burglary or other forms of criminal activity but were generally not aware these crimes had come about because of loan shark activity in the area. It was something that fell between the cracks. It wasn't recognised by the police as it wasn't in their key performance indicators."

But surely people wouldn't turn to loan sharks if it were not for the fact that they were unable to get credit through legitimate organisations?

Alan agrees, and says that some of the money seized from loan sharks is now being put into credit unions to assist their victims and others in financial difficulty.

"There's no doubt that some of those who can't get credit from a legitimate source regard loan sharks as their friends. We have colleagues in Scotland who've had to fight their way off an estate where people wanted to protect a loan shark.

"We're trying to help those who tell us they have nowhere else to go to borrow money through working closely with credit union such as the Bristol Credit Union.

"We're members of the Bristol Financial Inclusion Task Force and will be working closely with the newly appointed Financial Inclusion Champion for Bristol.

"We're using the Proceeds of Crime Act, which has traditionally been used for people dealing drugs. We'll not just take money from the loan sharks – we'll also take their houses and their cars. If you put these people inside for three months it doesn't touch them, but it does if you take their property and stop them carrying out their business."

The loan shark hotline advertised on the toy sharks, key rings and pens on Alan's desk is also an attempt to help people who have got money from loan sharks.

"It's something people don't find easy to talk about it. They're ashamed to have got into so much debt, and they're scared. We've put a lot of work into getting the 0300 1234 247 number out to people. We've put it in hospitals throughout the South West, in doctors' surgeries and libraries, and we've advertised in The Big Issue.

"It's paying dividends now. We're getting a considerable number of calls. We even had a call from a man in Wales the other day to say his brother has got problems with loan sharks in the North. On this number callers can speak to someone in confidence 24 hours a day, 365 days of the year.

Anyone who does contact the hotline will also discover something that could immediately transform their situation.

"Loans made by someone who doesn't have a consumer credit licence are not legally enforceable.

"The biggest message we have to anyone who has obtained money from a loan shark is that they don't have to repay it. It's not legally enforceable."

Have you been the victim of a loan shark in Bristol? If so, send an email in confidence to epnews@bepp.co.uk