Tourists wanting to visit the next big thing in London will have to wait until after the weekend and even then they'll need to book well in advance.
The 310m-tall Shard, which its designers hope will rival the London Eye and Big Ben as an icon of the city's skyline, opened to the public today.
The opening day was sold out with 4800 people taking the 60-second trip up to the 250m-high observation deck on floors 68, 69 and 72.
Tickets are unavailable this weekend, but can be purchased for later dates - as long as visitors book in advance.
Some have criticised the Shard - an arrow of glass pointing skywards - for being an ostentatious symbol of wealth.
But the firm promoting the observation deck of western Europe's tallest building defends the entry fee of £25 for adults and £19 for children.
"While on the face of it that could seem quite high, when you compare like-for-like with any other pre-booked attraction, you'll find it's in line with others," spokeswoman Nazneen Nawaz told AAP.
"It's absolutely perfect for new visitors to the city."
Operators say on a clear day the 360-degree view stretches up to 64km and takes in many of London's major landmarks, including Buckingham Palace, the Houses of Parliament, St Paul's Cathedral and the 2012 Olympic stadium.
Friday's opening was marked by poor weather, but people who visit when conditions are bad, while not entitled to a refund, can return another time free of charge.
The observation deck is also fitted with state-of-the-art telescopes showing a digital image of what the outlook would be like - during the day, at sunset, and at night - when conditions are clear.
Ms Nawaz said her favourite time to view London was sunset when the city's lights begin to come on.
