They unveiled The Shard during a ceremony held inside the building's lobby and were then given an exclusive visit to the viewing gallery on level 69.
The event marked the physical completion of the exterior of the building - which is fast becoming one of the most recognisable London skyline silhouettes. The inauguration represented the culmination of a 12-year journey to build a significant new landmark on the London skyline. Designed by renowned master architect Renzo Piano and developed by Sellar Property, The Shard now stands at 310m (1,016 ft). The Shard's 95-stories will become a 'vertical town' comprising office space, residences, restaurants, the five-star Shangri-La Hotel and The View from The Shard viewing galleries.
The inauguration was also marked by a spectacular light and laser show which illuminated the building that night.
The Shard is owned by LBQ Limited, comprising the State of Qatar (the majority shareholder) and Sellar Property, with non-equity funding by Qatar National Bank.
Commenting on the inauguration, His Excellency Sheikh Abdullah Bin Saoud Al Thani, Governor of Qatar Central Bank and Chairman of the Board of Directors of the Shard Funding Limited and London Bridge Quarter, said, "Standing at almost 310 metres, The Shard will be one of the tallest buildings in Western Europe. For me however, the height of the Shard is only secondary. What is special is the solid and continuing relationship between two nations -Qatar and Britain - which has been an important factor in completing this project."
He added, "The Shard has already become an important symbol for London - a symbol of our close relationship - rooted in the foundations of economic growth, social development and mutual trust and goodwill."
Irvine Sellar, Chairman of Sellar Property and partner of LBQ Limited said, "Today marks the physical completion of The Shard. It is a major step towards the ultimate realisation of our vision for London Bridge Quarter - a new dynamic district for our city with The Shard at its centrepiece."
The Mayor of London, Boris Johnson, said, "The Shard is more than just an amazing feat of engineering, it is a towering illustration of London's determination to beat the recession and spur economic growth. This iconic, sparkling new addition to the capital's skyline will act as a huge commercial magnet, pulling in scores of new businesses and offering vital employment opportunities for thousands of people."
Internal work is continuing on The Shard and it will be open to the public in 2013.