Cyberspace blackmailers have hijacked the website that earned a British student entrepreneur more than $1million in advertising sales. A criminal gang, suspected to be linked to the Russian Mafia, is demanding $50,000 to call off an online attack which today caused the site to crash.

Alex Tew, the 21-year-old founder of milliondollarhomepage.com, started the project in August to tackle his student debt. The site, which was divided into 10,000 tiny squares that were sold to advertisers for $100 each, made headlines around the world when it hit its target earlier this month.

But the publicity also attracted the attentions of a criminal gang calling itself the "The Dark Group", which sent Mr Tew a ransom note via e-mail on January 7 demanding $5,000 (£2,830). The group, which investigators suspect is based in Russia, threatened: "We're capable to take your site down".

When Mr Tew refused to pay, the gang waited a week before launching an attack that threatened to overwhelm the website and cause it to crash last Thursday. On Friday, Mr Tew received a second ransom e-mail, this time demanding $50,000.

The e-mail, which has since been resent daily, said: "hello u website is under us atack to stop the ddos send us 50000$ … if u do not pay -u site NEVER came online … -u have BIG problem with u sponsors … u must answer TODAY."

This morning, Mr Tew told Times Online from his home in Cricklade, Wiltshire, that despite efforts to improve the site’s security, the hackers had stepped up their attack. Visitors to milliondollarhomepage today met with an error page that said: "error 403 – forbidden … don't come back you sly dog!"

"There are some ruthless people out there, but to be honest, I expected something like this to happen as the profile of the site increased," he said.

"At the moment I’m too busy to ponder the moral implications of it – 2,000 people have paid me $1 million between them to advertise on the site and I am focussing on getting the site up and running again."

The poor English used in the ransom e-mails and the kind of DDoS – or distributed denial of service attack – used by the hackers to crash the site has led investigators to suspect that the gang behind the attack is based in the former Soviet Union, a notorious hotbed for cybercrime. However, DDoS attacks, which crash websites by flooding them with more traffic than they can deal with, can be very difficult to trace.

Mikko Hyppönen, the chief research officer for F-Secure, a leading internet security company, said these types of attack have became increasingly common in recent years. Most attacks are launched from infected home computers which can be controlled through internet viruses released on to the net by malicious hackers.

"Criminals usually target businesses such as online shops, which will lose money as soon as their website is offline, or sometimes we see companies targeting competitors, hoping to put them out of business. In this case people know that this guy has money," he said.

Mr Tew has met with the Wiltshire branch of the National Hi-Tech Crime Unit to pass on details of the attacks. He also expects to be contacted by the FBI, which is also investigating the hijacking and attempted extortion because the servers that host the site are based in the United States.

Under the terms of his website, Mr Tew has agreed to host his clients' adverts for five years. However, there is a clause which allows the website to be out of action for maintenance, which he hopes will cover the current disruption. It is unclear whether he has been hit financially by the attack.

However, the milliondollarhomepage.com is still destined to become a business school case study, with academics heaping praise on its "brilliant simplicity".

Flush with funds, Mr Tew, whose previous jobs include stacking shelves in Tesco, left his home last autumn to start a business degree at Nottingham University. Having completed his first term – during which his web venture earned him some $4,000 a day - he has now decided to defer his studies until September in order to "explore some of the new opportunities that have presented themselves".

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