London Shard to become Europe's first 'vertical town'

"Any development or any project or any business that takes a period of twelve years, you're going to have moments. But we've had a lot of support, externally and within my own team, and we've always been confident that we're going to get there, and we've got there. We've got there on the physical completion front but we've still got a lot of work to do," he said.

The Shard, so called because of its resemblance to a gigantic glass splinter, has yet to be finished but this week marks the completion of its physical exterior.

Designed by Italian Renzo Piano, the Shard is expected to draw rich customers from all over the world. But built close to some of London's most deprived areas, the tower has drawn criticism from those who see it as an example of wasteful spending at a time of economic uncertainty.

The building has also been accused of dominating the area and ruining views over traditional landmarks such as the Tower of London and St. Paul's Cathedral.

But Piano says the Shard is a phase in London's natural evolution.

"Every classic building has been modern at one time and this is where cities are great places because they are made by layers and every new layer is built on the old layers, at one condition - that you don't destroy, and we didn't destroy anything. We are right on the middle of a brownfield, coming from railways and this is the destiny of cities today, even historical cities, that you have to stop to grow by explosion, creating new periphery, new slums, and they have to increase, intensify from inside," he said.

Analysts say the Shard's developers have been spared from market wrath solely because the building was built with funding by the deep-pocketed royal family of Qatar, rather than a publicly listed firm.

But a January report by Barclays Capital pointed to a correlation between new skyscrapers and hard financial times, saying construction of the Empire State Building and some other landmarks coincided with economic crises.

The CEO of the Qatar National Bank said a firm belief in the UK property market was the key to its success.

"Most of the people are wondering how this building at this size came to life during a really very difficult time in UK market and also across the world. But from day one, we had a very great belief in the UK market and especially London," said Ali Shareef el-Emadi, in London as part of a delegation of Qatari royals who have flown in to see the coming of age of their 1.5 billion pound creation.

London's skyscrapers are modest compared with those of other financial centres in the Americas, Middle East and Asia. The Shard even remains lower than New York's Empire State Building, completed more than 80 years ago, and it falls well short of half the height of the Burj Khalifa tower in Dubai.

But once completed next year, the Shard will boast some of Europe's highest and most expensive flats, as well as restaurants, offices a hotel and a viewing gallery.

Qatar's central bank governor, Sheikh Abdullah Bin Saoud al-Thani, said there was no expectation of a quick return on their investment.

"Recover of the investment, or recover of our investment, it is a minor thing for us at this moment. We look forward to have this investment sometimes in the future," he said.

Towering 310 metres (1,016 feet) over the south bank of the River Thames, the Shard already dominates London like no other building.

The hotel should be open for business next year, and the developers predict full occupancy by the end of 2014.

On Thursday night, Londoners will be treated to a spectacular laser show to be projected from The Shard to mark the official completion of the exterior.