%VIRTUAL-SkimlinksPromo%Barclays customers' details are to be sold to rival companies and Government departments for the first time, the bank has announced.
Millions of consumers with Barclays savings and current accounts will have "information about the transactions on your account" collected and shared as a result.
According to the Daily Telegraph, the bank is also planning to start tracking customers through their mobile phones or other "devices" - to help protect them from fraud - from October this year.
So if a payment is made in a certain country, for example, Barclays will "ping" the customer's mobile number to check the customer concerned is there.
This is all likely to sound worryingly like Big Brother to many Barclays customers. The high street bank is far from the only business to share more customer data, though.
Supermarket chain Tesco has been selling on the customer data gathered via its Clubcard loyalty card scheme, which has been running since the 1990s, to food and drink companies for many years.
And just days ago, mobile phone operators Vodafone, EE and O2 said they would start selling bundles of anonymised data on their customers to big advertisers to help them come up with targeted campaigns aimed at different age groups and demographics.
Barclays also argues that its new approach to customer information, which has been laid out in changes to terms and conditions that are being sent to customers around the country, will always protect the customer's identity and will in fact have some positive effects for its customers.
According to website The Drum, the bank said: "We only use information in a numerical, anonymised and aggregated way as is standard practice at many companies.
"Mobile location data will be used for fraud prevention purposes only and therefore only on the occasions where this is a transaction on a customer's account that has been picked up by our fraud detection systems."
Those who prefer not to have their mobile phones tracked can also choose to opt out of this new service.
However, anyone unhappy about their data being shared may prefer to start banking with a building society, which is less likely to sell customer information on to other companies.
10 things we hate about our banks
Barclays bank to sell on customer data
More than 46,000 of 106,000 the complaints received by the FOS in the second half of last year related to payment protection insurance (PPI). And the organisation is expecting to receive a record 165,000 PPI complaints in 2012/2013.
The huge numbers are due to the PPI mis-selling scandal that should now be a thing of the past, but there is no doubt that the insurance, which can add thousands to the cost of a loan, is highly unpopular!
(Pictured: Martin Lewis after the PPI payout ruling)
Complaints about mortgages jumped by 38% in the last six months of last year, the FOS figures show, compared to an increase of just 5% in investment-related complaints.
Common gripes about mortgages include the exit penalties imposed should you want to sell up or change you mortgage before a fixed or discounted deal comes to an end, and the high arrangement fees charged by many lenders.
While there is nothing in the data released by the FOS about the number of complaints relating to savings accounts, hard-pressed savers have been struggling with low interest rates for several years now.
You can get up to 3.10% with Santander's easy-access eSaver account, but many older accounts are paying 1.00% or less and even this market-leading offer includes a 12-month bonus of 2.60% - meaning that the rate will plummet to just 0.50% after the first year.
Banks are imposing the highest authorised overdraft interest rates since records began, with today's borrowers paying an average of 19.47%, according to the Bank of England.
A typical Briton with an overdraft of £1,000 is therefore forking out around £200 in interest charges alone. Coupled with meagre returns on savings, it's enough to make your blood boil!
While authorised overdrafts may seem expensive, going into the red without permission will cost you even more due to huge penalty fees.
Barclays, for example, charges £8 (up to a maximum of £40 a day) each time that there is not enough money in your account to cover a payment.
If you need to send money abroad, the likelihood is that your bank will impose transfer charges - and offer you a poor rate of exchange. Someone transferring a five-figure sum could easily lose out by £500 or more as a result.
The good news, however, is that you can often get a better deal by using a currency specialist such as Moneycorp.
Automated telephone banking systems, not to mention call centres in far-flung parts of the world, are one of our top gripes - especially as we often encounter them when we are already calling to report a problem.
In the words of one disgruntled customer: "What is it about telephone banking that turns me into Victor Meldrew? Well, maybe it's the fourteen security questions, maybe it's the range of products that they try to push or maybe it's because I'm forced to listen to jazz funk at full volume while my phone bill soars.
"Actually though, I think it's because the people I eventually speak to rarely seem able to solve the issue I'm calling about."
The days of a personal relationship with your bank manager are long gone - for the huge majority of us at least.
When ethical Triodos Bank investigated recently why around 9 million Britons would not recommend their banks to a friend or relative, it found that almost a third felt they were not treated as individuals. Another 40%, meanwhile, were simply disappointed with the customer service they received.
When you're in a rush, the last thing you want to do is wait in a long queue at your local branch.
Researchers at consumer champion Which? recently found that most people get seen within 12 minutes, but you could have a much longer wait if you go in at a busy time. Frustrating stuff!
The Triodos Bank research also indicated that the bonus culture that ensured the bank's high-flying employees received large salaries, even when it was making a loss at the taxpayer's expense, was hugely unpopular with consumers.
About a quarter of those who would not recommend their current banks said this was the main reason why. And with RBS executives sharing a £785 million bonus pool despite the bank, which is 82% publicly owned, making a loss of £2 billion last year, it's not hard to see why.