The sculpture is based on Pinocchio

American artist Paul McCarthy has distorted the familiar pointy-nosed puppet-boy into a intimidating figure, which sits on a pile of books and has a cube for a head.

Rising above the River Thames, Blockhead is situated outside London's Tate Modern gallery and goes on show from Monday.

Visitors will be able to enter the installation through an opening in the base, and can buy specially-made sweets from inside the cavernous hallway.

Mr McCarthy says it is like standing at the bottom of a cliff, describing Blockhead as "an abstract that rises up and over your head".

"This is one of the largest inflatable sculptures made, as far as I know," a Tate spokeswoman said.

As high as the Tate

"It's the height of the Tate Modern building - not including the chimney.

"It's a big surprise because it's so huge. I've noticed lots of smiles creeping across people's faces."

Alongside Blockhead will be a second new work by the artist, entitled Daddies Bighead.

Half the height of Blockhead, the second piece is also inflatable and is based on a ketchup bottle.

Tomato sauce is a continuing theme in the 58-year-old artist's art.

He has used it to represent bodily fluids and often focuses on consumer culture.

In the 1970s, he was known for his performance art.