The UK Pavilion has the potential to become one of the world's great architectural designs, outweighing even the Expo's top attraction, the China Pavilion, according to one of China's preeminent designers.

Known as the "Seed Cathedral", the pavilion is the most extraordinary structure in the Expo Garden, said Jiang Huancheng, a Chinese engineering academic and the designer of Shanghai's landmark Oriental Pearl Tower.

"The structure itself is a showpiece and conveys the message of environmental awareness," Jiang said.

Created by British architect Thomas Heatherwick, the UK Pavilion is unique, formed from 60,000 slender, transparent rods, each of which is 7.5 meters long, encasing one or more seeds at its tip.

By day, they act as optic fibers, drawing daylight inwards to illuminate the interior. By night, light sources inside each rod allow the whole building to glow. As the wind blows, the building and its optic "hairs" gently move to create a stunning effect.

Despite its popularity, the structure has also drawn criticism because of its small interior (about 100 square meters), and the fact it offers little by way of exhibits. But this hasn't stopped visitors - many of whom wait hours just for a 10-minute tour inside the pavilion.

The pavilion's design team argues that the exhibition space is not an important overall feature of the pavilion - rather, it is the exterior and what it represents that is the most important aspect.

But despite complaints about the interior, Jiang sticks by his observation that the UK Pavilion is the most architecturally significant in the Expo Garden, though he admits there are plenty of other attractions among the other pavilions.

"The German Pavilion looks like a chariot, while the France's public face at the mega event shows its romantic features," Jiang said.

The China Pavilion, on the other hand, which features a pyramid style, has its own problems, however, said Jiang.

"The China Pavilion is successful as a landmark, and this can be seen from the crowds of people taking pictures of it," Jiang said.

But the structure itself has defects when seen as a building for exhibitions, he said.

Most notably, he said, visitors must be ferried by elevator to the upper floor, where the main exhibition hall is located, before being brought back down by escalators. This requires a lot of staff to organize and may possibly inflict difficulties in case of fire, Jiang said.

A typical exhibition hall will always accommodate a majority of its visitors on lower floors.

The six-month Expo is another sign of China's growing global clout following the 2008 Beijing Olympics, he said. "The fair offers a splendid display of architecture," Jiang said. "All countries have shown their unique characteristics."