UK consumers are unwittingly helping hackers target e-business firms by leaving themselves "woefully unprotected" from spam, key-logging and phishing attacks, research has claimed.

A newly published poll of 11,000 UK residential email users and small to medium sized businesses (SMEs) found that users are the weakest link for banks, retailers and other online businesses, offering hackers "an easy way in".

The study, commissioned by email filtering managed service provider Checkbridge, indicated that almost two thirds of consumers and SMEs have no anti-spam filtering installed.

However, the report noted that it is not financially or technically viable for residential users or small businesses to arm their desktop with all the filters required to provide corporate-level protection. Over half of consumers and 62 per cent of SMEs recognise that multiple scanners are now required.

"Market debate for some time now has centred on the vulnerability of corporations. Consumers and SMEs, and their interaction with corporations, are a neglected and critical link in the national armoury," said John Turley, managing director at Checkbridge.

"It is in the banks' and retailers' interests to get consumer protection right, whether by approaching government, endorsing those ISPs that offer sufficient protection or paying for secure telecoms infrastructure (e.g. VPNs) for their client base."

The results of the survey arrived in the same week that HSBC announced that it may refuse customers access to online banking unless they show that they have adequate protection.

In the fight against credit card fraud Mastercard has closed down 1,000 sites containing details of 35,000 credit cards. Apacs, the UK payment association, believes that phishing attacks cost banks £12m last year.