The desperate search for Madeleine McCann has been hijacked by conmen cashing in on her family's heartache.

The official website, launched to help find the missing four-year-old, has received more than 70million visits in three days.

In a sickening ploy a series of Internet sites with similar names have been created to exploit its high profile.

Some of them are filled with adverts, including many from well-known British brands such as Abbey, the BBC's Good Homes magazine and Bryant Homes, while others even divert users to gambling or pornographic websites.

Every time someone clicks on one of the Internet links, the firm which set up the website is paid a fee by an advertising agency.

It is feared that hundreds of thousands of genuine well-wishers have inadvertently visited the fake 'typosquatting' websites simply by misspelling Madeleine's name.

The genuine site is accessed by www.findmadeleine.com or www.bringmadeleinehome.com.

The McCann family reacted with anger and disbelief that their campaign could be so cynically exploited.

Madeleine's uncle John McCann said: "We are incredibly disappointed that people are taking advantage of people's generosity and using it for commercial gain, rather than charitable purposes.

"It is a shame that people behave like this and they exploit the generosity of the general population."

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A picture of Madeleine is shown on the big screen at the FA Cup Final

He continued: "I am loth to use the phrase parasites, but unfortunately that is what it seems like.

"It is up to people to be aware and it is up to us to circulate the official website name to make sure that when people search for Madeleine's site they get the right one."

So-called 'typosquatting' is a growing menace on the Internet and involves registering domain names similar to those of popular websites.

Some bogus sites are set up to imitate the original with the intention of fraudulently obtaining personal details, such as bank account numbers.

Others simply aim to increase traffic to their own services or sell advertising space.

One of the companies exploiting the popularity of Madeleine's website is Californiabased UltraRPM.

The firm registered at least three domain names similar to the official site this week, one with just a single letter missing.

It then used a 'domain parking' company called Trafficz.com to manage the site and fill it with adverts from mainly British companies whose advertising agencies pay a fee for each visitor who clicks on the links.

The fees are usually no more than about a penny a click, but can rise up to ?40 in some cases.

Maddy in her Everton football top

Household-name companies on the websites reacted angrily and demanded the sites be withdrawn.

A spokesman for Abbey said: "We knew nothing about this. All our Internet adverts are managed by a private company.

"It looks like this fake site is using a search engine as lots of companies have appeared on it. We are doing our best to remove the advert as quickly as possible."

A spokesman for Bryant Homes said: "We will alert our national advertising agency to this and remove the advert as soon as possible."

An eBay spokesman said: "If adverts for eBay appear inappropriately on the Internet, we take immediate steps to have them removed. Where this occurs, we would never again work with the organisation or individuals responsible."

And Barratt Homes said: "This is totally unauthorised and totally unacceptable. We have demanded that the link be removed immediately."

Internet expert Colin Sweetman said 'typosquatting' could be extremely lucrative. "If you misspell any well known company's website address you are likely to end up on a typosquatting site.

"I always advise clients who are setting up a website to buy the domain names which are close misspellings of their company's name to avoid this kind of problem.

Miss you: Amelie McCann, two, with her sister's favourite toy Cuddle Cat yesterday

"People doing this are mainly operating from the U.S. but it's spreading rapidly.

"There is no way that advertising agencies will not be aware of this phenomenon. But until the profile of this is raised it will continue.

"When it's the misspelling of something like Google, that's one thing, but to capitalise on the disappearance of a little girl is a despicable practice."

The official website received more than five million hits in its first 24 hours and visits have multiplied.

At one stage more than a million were viewing pages at the same time.

The phenomenal interest is a clear indication of how deeply Madeleine's disappearance has seared itself into the public consciousness.

That is precisely what the McCann family intended. But even they were 'overwhelmed' yesterday by the massive numbers of people who have shown support or are trying to help by keeping Madeleine's profile so high.

The exploitation has deeply upset Madeleine's parents Gerry and Kate.

Mrs McCann's uncle Brian Kennedy said: "We can't put into words how we feel about these people. If they are using Madeleine's website to make money it is extremely unpleasant."

Jon Corner, 48, godfather to Madeleine's sister Amelie, said: "This is outrageous.

"I'm extremely disappointed that the genuine efforts of the family to try and get as much exposure as possible to get their daughter home is being exploited for a quick buck."

Mr Corner, who runs a production company and helped set up the genuine website, added: "The vast majority of people are appalled by the abduction of this beautiful little girl and have been amazing in the love and support they have given.

"But this shows there's another side of human nature that is prepared to use this terrible situation for their own gain.

"We should try to remember that they are in the minority, though."