London's iconic billboard at Piccadilly Circus has been switched on for the first time in nine months - with a high-tech and controversial makeover.

The six old advertising boards have been replaced with one high-definition curved screen, dubbed the 'Big Brother billboard'.

The screen features facial and object recognition technology to track passing cars and pedestrians and deliver targeted adverts.

It also provides free Wi-fi which researchers have warned could be used to 'monitor and capture your every online move.'

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A huge 'Big Brother billboard' has been switched on in London 's Piccadilly Circus that can track passing cars and pedestrians to deliver targeted adverts. It also provides free Wi-fi which researchers have warned could be used to 'monitor and capture your every online move'

WHY IS IT CONTROVERSIAL? The company behind the billboard, Landsec, says no personalised data or video or photography is recorded or stored. But some have still raised concerns about the nature of the billboard's surveillance - saying it could be used to monitor people, particularly with its use of free WiFi. 'The reality of this digital game is that the free WiFi you connect to is the real gold-mine for the sponsors of this technology', cyber-security expert Douglas Crawford from BestVPN.com, told MailOnline. 'Savvy customers who want to protect their privacy from prying eyes are advised to use a VPN to stay one step ahead of the businesses desperately trying to capture their data.' Advertisement

A digital countdown marked the return of the lights to Piccadilly Circus at 8am on this morning.

The billboard was replaced by a temporary banner after being turned off in January, marking the longest period of darkness since the Blitz.

HOW DOES IT WORK? The vast screen - which is around the size of four tennis courts - uses features recognition technology to target people with hidden cameras. The hidden cameras track the make, model and colour of cars as well as the age, gender and even feelings of pedestrians. Brands can also pre-program triggers so specific adverts are played when certain car models pass, for example, according to Landsec who own the screen. 'The reality of this digital game is that the free WiFi you connect to is the real gold-mine for the sponsors of this technology', cyber-security expert Douglas Crawford from Best VPN, told MailOnline. 'They can use it to monitor and capture your every online move.' Advertisement

'Very lucky to witness #PiccadillyOn at 08:00 this morning looks amazing', wrote commuter Simon Tann on Twitter.

After being switched on for the first time in nine months, the electronic hoardings have been replaced with a state-of-the-art screen which is around the size of three tennis courts.

The hidden cameras track the make, model and colour of cars as well as the age, gender and even mood of pedestrians, according to The Verge.

Brands can pre-program triggers so specific adverts are played when certain car models pass, according to Landsec who own the screen.

Every ten minutes a single brand will fill the screen for 30 seconds.

Coca-Cola, Hyundai, Samsung and L'Oreal will be the first brands to use the space, writes Wired.

For the rest of the time, the screen, which is 8,500 square feet (790 square metres) will be divided into six and will stream video, sports and social feeds.

'The new screen has the ability to react to external factors such as the weather and passing vehicles - though without collecting or storing any personal details', a spokesperson for Landsec told MailOnline.

'For example, the branded content displayed on the screen could change depending on the colour of vehicles.

'How the technology is used depends on the approach and creative being displayed by the brands', the spokesperson said.

Speaking earlier this year, Tim Bleakley, chief executive of Ocean Outdoor, the company that runs the board’s advertising said: ‘Coca-Cola, for example, can log on at any given moment, see a large group of Spanish tourists and change the copy of the ad from ‘hello,’ to ‘buenos dias’.’

The screen features facial and car recognition technology to target people with hidden cameras, meaning it shows adverts based on an individual's age, gender, mood and the vehicle they drive

After being switched on for the first time in nine months, the electronic hoardings have been replaced with a state-of-the-art screen which is around the size of three tennis courts. Pictured are people photographing the new screen

He told the Daily Mail: ‘The facial detection just detects things that seem likely rather than identifies specifics.

Very lucky to witness #PiccadillyOn at 08:00 this morning looks amazing pic.twitter.com/EGBEk319PE — Simon Tann (@TannSimon) October 26, 2017



‘It’s a snapshot in time done in seconds and no personalised data or video or photography is recorded or stored.’

Mr Bleakley said similar technology is already being used on electronic billboards in other locations, including at car park barriers.

He said the giant smart billboard is dynamic in that it can constantly change to reflect what is going on around it.

For example, he said a fashion brand could change its images if it rains, perhaps promoting coats and boots.

Brands can pre-program triggers so specific adverts are played when certain car models pass, according to Landsec who own the screen

Every ten minutes a single brand will fill the screen for 30 seconds. Coca-Cola, Hyundai, Samsung and L'Oreal will be the first brands to use the space

For the rest of the time, the screen, which is 8,500 square feet (790 square metres) will be divided into six and will stream video, sports and social feeds

A drinks brand like Coca-Cola can add ice to their commercials on summer’s day when the temperature hits a certain figure.

And brands can change the themes of their ads based on the mood of the day as measured by traffic on social media, in terms of whether London is happy or gloomy.

A car company can also trigger an ad to run if a specific make, model or colour vehicle passes by.

However, some have raised concerns about the nature of this surveillance - saying it could be used to monitor people.

'The reality of this digital game is that the free WiFi you connect to is the real gold-mine for the sponsors of this technology', cyber-security expert Douglas Crawford from BestVPN.com, told MailOnline.

A drinks brand like Coca-Cola can add ice to their commercials on summer’s day when the temperature hits a certain figure

'They can use it to monitor and capture your every online move.

'Savvy customers who want to protect their privacy from prying eyes are advised to use a VPN to stay one step ahead of the businesses desperately trying to capture their data.'

The screen produces 281 trillion colours and each pixel is 8mm from the next - giving it extremely high-definition images.

'One has to wonder how successful this campaign would be, given the sheer traffic passing through on an hour to hour basis', Jovi Umawing, a researcher at Malwarebytes told MailOnline.

The screen produces 281 trillion colours and each pixel is 8mm from the next - giving it extremely high-definition images. Pictured is the old screen that was switched off nine months ago

'If this system were used in a less populated area and collected information, it could be something worth actively avoiding', she added.

The giant screen replaces the six screens that were there previously.

An illuminated billboard has been in Piccadilly Circus for more than 100 years.

The space was first used to advertise Perrier bottled water.

The original light bulbs were replaced by neon signs later in the century, which were in turn replaced by digital projectors in 1998.