Traditional 'retail' banks are most at risk, according to a survey by Deloitte Consulting, which talked to senior executives of 133 banks and insurance companies around the world.

These banks, which provide High Street customers with loans, mortgages and current accounts, could lose up to 25% of their profits over the next five years.

Cherry picking

Most retail banks rely for their profits on a very small number of well-off clients. At a typical retail bank about 20% of its customers generate nearly all the profit, effectively subsidising poorer account holders.

Cheques are expensive to process; online banking costs a few mouse clicks

But now cherry-picking competitors are moving in. They poach the wealthy clientele by offering attractive financial packages and new services.

Technology is the driving force. Online and telephone banking cuts costs; better interest rate deals are the result.

Meanwhile, smarter database management and marketing techniques allow the newcomers to target the well-off customers.

The competitors

The assault is coming from several directions.

• Upstarts
  They offer online and telephone banking and tend to specialise on just a few financial products, for example current and savings accounts, or cheap mortgages and insurance deals.
• Specialists
  Some banking business is more profitable than other financial products. Single product operators, offering credit cards for example, can be leaner and more competitive than traditional banks.
• Financial cross-over
  Insurance companies, with their wealth of experience in other financial sectors, invade the banking sector, making use of their vast customer data bases and new technology.
• Retailers turned bankers
  Even companies without any experience of the financial sector are now taking the plunge. Many supermarkets, car manufacturers and other retailers are now offering financial services which go beyond the traditional store credit cards or cheap loans for the deal on wheels.

Sorting out your account online could be the financial future

Others, however, lag behind and risk seeing their profits dwindle as customers flock to financial service providers like Virgin Direct, which has huge success with its PEPs and current accounts and Sainsburys and other supermarkets who now offer banking services.

Customer turnover

European banks will have to brace themselves for tougher times. Until now their 'customer churn' - the number of people switching their current account from one bank to another - has been low, only 3%.

But if the development in the United States is anything to go by, the numbers will go up fast.

First Direct, for example, claims that it is signing up 12,500 new customers each month.

MBNA, a US-based credit card issuer which came to the UK several years ago has now snatched a market share of 10-15%. One of its main competitors, Barclaycard, was recently forced to sack over a thousand workers as its business slumped.

Banking used to be a people business

Senior banking executives across Europe are worried. The Deloitte Consulting survey shows that 83% of them see retailers and even software companies as a significant factor in the future market place. 85% believe that customer loyalty will be a major concern for the future.

And many banks are just not prepared. Only 20% of executives questioned for the survey believe that their bank has done enough to keep customers on board.

According to Deloitte, the banks have reacted so slowly because they have been spoilt by strong profits in the past.

They are also hindered by out-dated computer systems that prevent them from targeting and servicing their customers in the same way as upstarts do.

Generation gap

But many people do not know how to operate a computer, never mind setting up an online bank account.

John Harrison, partner with Deloitte Consulting, predicts that the generational gap between computer-savvy 30-somethings and the rest of the population will soon disappear.

Deloitte predicts that Online banking will imitate the success of cash points

He believes that computer banking will follow a similar path as Automated Teller Machines (ATMs).

These cash points were quickly accepted by younger people. The market was then stagnant for five years, before the technology finally took off.

Mr Harrison forecasts that customers will switch as the new banking technologies get more established. In 10 years, he says, the majority of Europeans will have their account on the Web.

John Reeve, also a partner at Deloitte Consulting, calls it a "watershed in the evolution of the (banking) industry".

Security concerns

But are customers really prepared to hand over their money to a computer, instead of depositing it with a bank clerk in a proper bricks-and-mortar building? Is online banking safe?

John Harrison says he would be more worried giving his credit card to a waiter in a restaurant than passing on his financial details to a trusted bank on the Internet.

Fighting back

So how can traditional retail bankers fight back?

For starters they will need money, and lots of it. Deloitte's experts estimate that a bank will need to invest up to $160m (£100m) to get up to speed.

Besides the new technology, they will need to re-focus their marketing. Mr Harrison says banks will have to target and tailor their services for up to 25 to 30 different customer segments. Only then will they be able to retain those which generate profits.