The graphics extend to some 41m wide and include the biggest 2012 logo yet in the capital. They were produced and fitted by St Ives subsidiary Service Graphics.

The Olympic messaging appears on both sides of GSK’s landmark HQ in Brentford, which is adjacent to the elevated section of the M4 motorway. GSK estimates that more than 78,000 people a day will see the graphics as they travel in and out of London.

GSK chief executive Andrew Witty described the signage as "the perfect way" to celebrate GSK’s involvement with the games. "Millions of people will see it in the lead up to the Games and during Games time itself," he said.

The sign was officially unveiled by Team GB cyclist Rebecca Romero last week.

GSK media manager for 2012 Diana Evans said: "We spent a year planning everything. It’s the first time we’ve put anything like this on the building and it’s going to be up for a year. It was very important that we found the most appropriate material for the building."

The company is providing laboratory services for anti-doping drug tests during the Olympic and Paralympic games.