Nick Sayer of B2C Data boasted to an undercover reporter saying he had persuaded 250 British companies to pass on detailed information

It is a firm you will never have heard of – but it boasts that it knows everything about you.

From your salary to the ages of your children and even which DVD you rented last weekend, B2C Data has a 'rich and complex' picture of every family in Britain.

Minutes into a phone conversation with our undercover reporter, the firm's sales director boasted it held 5,000 pieces of personal information for every household.

'Literally we know what clothes they buy, what health products they buy, where they go on holiday, how many times they go on holiday, what income they've got, whether they have children,' sales director Gareth Doran – a convicted fraudster – boasted from his home in Marbella.

Days later, over a pot of tea in a London hotel, his silver-haired colleague Nick Sayer casually revealed how this shadowy company had compiled such an extraordinary amount of data. Flashing his expensive silver watch as he sipped, he said he had persuaded 250 British companies trusted by millions to pass on detailed information about their customers.

Perhaps most shockingly of all, he claimed to have access to individuals' financial information – including confidential details of the size of their pension pots.

The information was obtained, he claimed, via a secret agreement between B2C and the UK's largest financial advice group. Through this deal – kept secret from customers under a non-disclosure agreement – he claimed he was able to access confidential details handed to mortgage advisers who worked with the finance firm. In return, he maintained their customer database for free.

'Whenever you fill in a mortgage application, you have to give your employment, your income, any investments,' he explained. 'We get all that information on a million people.'

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Supplying the financial data of 15,000 pensioners and investors to the Mail's fictional cold-calling company would be 'no problem'.

Sayer claimed to have similar deals with 250 household-name firms – including a high-street retail giant and a well-known holiday company. As a result, B2C had compiled an extraordinarily detailed picture of the lives of millions, he said.

He claimed to have access to individuals' financial information – including confidential details of the size of their pension pots

Every time someone books a holiday, buys a TV or applies for a mortgage with one of the major firms who supply data, B2C gets an update for its massive database. 'It's amazing,' he grinned. 'The more you dig into it... you think: Crikey, they know everything about us.'

The amount of data B2C holds – and the way it is selling it – was described by the Information Commissioner last night as 'on the face of it, a very worrying breach of the Data Protection Act'.

When explaining where B2C got its data from, Sayer claimed it was all agreed under a secret deal with the financial advice network Sesame – which processes one in six mortgage applications in the UK.

Sesame furiously denies any deal with B2C or Sayer and says it does not sell its customers' data under any circumstances. Last night independent experts compared a sample of the data provided to the Mail with that from Sesame and confirmed the data was categorically not on Sesame's database.

An urgent investigation is now underway into how Sayer was able to provide us with pensions and investments data on 15,000 people.

During the meeting, Sayer – the production director in charge of building B2C's huge database – smilingly admitted he had been dubbed a wheeler-dealer 'Del Boy' by friends but insisted the label was unfair.

He did admit it was his third attempt at running a data company, after giving up his career as a professional diver. But he shrugged: 'It's all business partner problems. First one done me for a load of money, second one turned out to be a cocaine addict and never showed up.' Sayer admitted the trade in personal data was a 'cut throat kind of industry'. There were, he said, 'a lot of very, very unscrupulous people in data' – adding quickly: 'I like to think I'm not one of them.'

But when the reporter told him she wanted to start a cold-calling operation selling investments to pensioners, he was more than happy to sell the salary, pension and investment details of 15,000 people, along with their addresses, ages and telephone numbers.

No checks were made on who our reporter's firm was, or for what it intended to use this information.

During the meeting he admitted he had been dubbed a wheeler-dealer 'Del Boy' by friends but insisted the label was unfair

The most basic enquiries would have revealed that the outfit he was selling to was fictional, as were the names he was given. The 'investment firm' comprised no more than a website and a few business cards. Yet Sayer said he had 'no problem' handing over as many pension records as desired. 'Rich people,' he said. 'You want people with the biggest pension pots you can find.'

Selling data on pensions was routine business for B2C, he said – particularly at the moment.

Pensions were currently 'hot business' and the company was selling on its detailed pension pot information 'ten times a month, maybe'.

'Everyone wants to know everything about these people,' Sayer added. 'So for example, you'll want the pension data, and you'll want to know what their pension pot is, what their income is, what sort of house value they've got, all that kind of stuff, which is fine.

'I don't mind putting all that on the data for you. I've got no problem with that.' However, he said our cold-callers should be careful not to reveal much information they had on people. 'Because we get a million people phoning us up saying, 'How do you know that?'.'

Days after the Mail's meeting with Sayer, our undercover reporters called sales director Doran, confirming we would like to buy the pensions data. Incredibly, Doran even suggested to our reporter that she could buy the data off the books – outside of the B2C business – as a way of avoiding the tax payable.

Mr Sayer, the production director in charge of building B2C's huge database, on a £17,000 Harley-Davidson

Doran, who has served a jail sentence for fraud after he was caught using fake bank notes, said this would be a 'favour to a friend'. He suggested she transfer £5,000 straight into Sayer's personal bank account to seal the deal, promising the data would be sent straight afterwards. When she told him she would rather buy the data through the business, he agreed – but asked that she 'please just keep the other option that we did talk about just between ourselves'.

When the Mail contacted the people on the database B2C sold us, they were understandably horrified. Not one of them had agreed for their financial information to be stored, used or sold in this way. Nor had they heard of B2C. However, many had long suspected they were on a list as they had repeatedly been targeted by cold-call conmen.

Disturbingly, some of the scammers even seemed to know details of their shares and investments – and had tried to use that information to rip them off. But why would firms risk their reputations by handing over sensitive financial data? Sayer explained that all firms need to have their customer databases 'cleaned', a laborious process which involves updating every detail.

As a result, they outsource the work but that can cost them between £1million and £2million a year, Sayer said. B2C offered to do it for free – as long as they could keep all the data.

The firms involved did not want to be publicly associated with B2C Data, he said. 'I don't normally tell anyone their names any more - it's kind of a non-disclosure thing.'

Last night B2C Data Ltd denied any wrongdoing, saying the company abided by all the proper laws and regulations of its industry. It confirmed that Gareth Doran had been suspended pending an investigation into the allegations he tried to sell data outside the business.

The poor and vulnerable? There's no hotter data

Data bosses described how they target vulnerable pensioners as 'the hottest leads' in secretly recorded meetings with Daily Mail reporters posing as representatives of a cold-calling firm.

They spoke openly of exploiting the recently bereaved and people who had lost their homes or taken out payday loans after falling on hard times.

'There can be no hotter data,' one said. 'They're vulnerable'.

Meanwhile, homeowners who dare complain when they are harassed by cold callers were ridiculed as 'screamers'.

The comments were made by data bosses from various firms in meetings with undercover reporters from the Mail. Here are some examples.

Businessman who preys on the poor

Vidya Mishra, 44, runs data firm Prospect 360 out of his £600,000 family home in Surrey. He claims it receives personal data from banks when people forget to tick the third party marketing box.

Information about small businesses is collated by cold-calling receptionists and asking for personal details about their bosses.

Data sold by Prospect 360 is understood to have ended up in the hands of fraudsters.

Vidya Mishra, who runs data firm Prospect 360, said: 'We got for those with young children. They're soft'

On payday loan customers

'There can be no hotter data. I can't ask for anybody more on a cold call than anybody who is in need of a payday loan. Undoubtedly, right? They're vulnerable.'

On will writing

'If you are targeting people over the age of 50, the likelihood is in the very near future they are going to suffer from bereavement – because their aunt Flo or their parents are going to die.

'And they're going to have to start thinking about it. And it just needs to get their mind ticking. Suddenly they receive a call from you and that's what prompts them.

'We go for families with young children because your world changes when you have children and everybody goes a bit soft.

'And they say, I want to give the best to my children. I want to make sure that they're safe.

So if I die tomorrow ... dah dah dah. That, for us, is an excellent profile.'

On targeting the poor for dental treatments

'Why is it that people from a lower socio-economic background have really poor teeth? Whereas more affluent areas, more educated people, more educated people's kids have better teeth?

'You see programmes on the TV all the time of kids who have got rotten teeth because they eat too many sweets and don't brush their teeth and stuff. Yet, for more affluent families, our kids don't have fillings or anything like this.'

On nicknames

'Before they become a prospect, we call them suspects. A prospect is somebody who is likely to buy your product or service. Before you've even contacted them, this is a suspect.'

On financial data

'You filled in that form innocently but you haven't ticked the box at the bottom. It's fair game.'

Boss who seeks out those in debt

David Billington, 50, runs Targeted Response Direct Ltd, which sells personal details filled in by those who have applied online for payday and unsecured loans but been rejected.

On people about to lose their homes

'We had a great data set. It was people who were basically being forced out, who were facing repossession. We got it through our direct contact, it was a source from the court. We were selling this data for about £4 or £5 a lead.'

On exploiting those in debt

'If you can find somebody and get them into an IVA [individual voluntary agreement] or a debt management plan, then there's money in it. And once they're out of the doo-doo, there's always the opportunity to offer them a loan again.'

Broker targets cold call victims

One of B2C Data's regular clients is Data Bubble – a broker which is believed to have sold on data to fraudsters.

The firm, run from a mobile home, compiles personal data from a variety of firms like B2C and then creates customised lists of targets for cold callers – including those who have opted out of receiving cold calls by registering with the Telephone Preference Service (TPS).

Its director Joanne Clayton, 46, recommends that clients should not tell the people they call how much they know about them.

On cold-calling those who have opted out

'You can get some people that are registered TPS that scream really. You get a lot of screamers. I would suggest on the calling script that you don't turn round and go 'Hi there Mrs Jones, I understand that you've got three kids and you've got a pension, how can I help?' Because otherwise that will scare Mrs Jones.'

Firm who claim 'we're good guys'

The bosses of The Data Partnership claim they are the 'good guys' in 'an industry rife with cowboys'. But John and Victoria Pooley's firm is cold-calling hundreds of thousands of people each month.