Advertisers are finding new ways to hone in on that very human weakness: the impulse buy.

Those tempted by sweets near a till may want to look away now, but technology has been developed that will give viewers the option to instantly purchase the products they see being advertised on screen.

The “hotspot” technology means that during an advert, bubbles pop up on screen alongside products. Viewers can click on anything they see that takes their fancy and then make their purchase at the press of a button.

As the latest fashions parade on screen, or as a seductive voiceover entices you to try out expensive new foods, people will be able to point at what has caught their eye and quickly fill their virtual shopping basket via their remote control.

The first use of the technology can be seen in a new Nike advertisement featuring Cristiano Ronaldo, the Manchester United star. As he runs around the pitch and strips off after a match, fans can click on his shirt, shorts and undergarments to buy them instantly.

The clip can now be seen online, but those behind the advert believe that once the switchover from the analogue to digital TV signal is complete by 2012, the technology will be utilised on television as well.

“Now you see the red button on screen, this is the next evolution of that,” said Luke Aviet, managing director of Go Viral, the company distributing the new advert. “As everything merges into digital, you will see this being used.”

Advertisers believe that “interactive advertising” is the future for impatient audiences who need a reason not to skip the programme breaks.

Jonathan Wilson, from Red Bee Media, who has worked on campaigns for Boots, Tesco and Citroën, said that a similar idea was showcased a few years ago, whereby those watching Friends could click on the clothes a star was wearing and buy them via remote control.

The technology to make this possible did not exist. But it looks set to become a reality now that most homes have a broadband internet connection, Mr Wilson said.

He said: “It has come to our screens now, albeit it's Ronaldo’s training top you can buy rather than Jennifer Aniston’s sweater.”

“Interactive ads that do more than make you appreciate the brand but actually take you on to the point of purchase, is already the trend,” said Alex Sullivan, an executive from the Fallon agency.

“If you’re talking to a young audience you need to keep it fresh, and new technology is the way to do that.”

Modern audiences, so used to product placement, have already come to see films and TV programmes as a form of window shopping. Websites such as ASOS.com, which stands for As Seen On Screen, sell women’s clothing featured in TV and movies. These have also proved to be hugely successful.

Soon viewers will be able to buy the items they see without having to leave their sofa. This is because, through digital TV, viewers will able to access online stores.

The Hotspot technology was created by the Bristol-based internet video company Coull, which is working on similar campaigns with companies such as Renault, Fiat, Littlewoods and Boots. Go Viral's internal research has shown that up to 30 per cent of people who see the Hotspot ads click through to find out more about the product.

“We’ve seen companies experimenting with this last year,” said Irfon Watkins, chief executive of Coull. “Now they are ready to roll it out.”

Ofcom predicted recently that the advertising market could collapse in the next decade because of the growth of the internet. A study conducted for Ofcom by Oliver & Ohlbaum Associates showed that conventional TV advertising revenue could fall from £3.16 billion in 2007 to just £520 million by 2020 – a drop of 83 per cent. As a result retailers are having to think of ways to reach their target audiences through both TV and computer screens.

The apparent simplicity of the technology is encouraging companies to investigate further uses for it. Nike said: “For something that seems very technical it's actually very simple and takes very little time.”

With digital set-top boxes providing the ability to fast-forward through advertising, and with hundreds of channels competing for viewers, companies are desperately looking for new ways to keep people tuned in during programme breaks.

It emerged recently that ITV is developing a new form of unavoidable advertisement that can be embedded in television programmes. The technology, which is known as “automatically placed overlay advertising”, uses complex computer algorithms to find clear space, such as blue sky or blank walls, in video footage in which to display logos or messages.

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