British police charged a 17-year-old with attempted murder after a six-year-old boy was thrown from a 10th floor viewing platform at the Tate Modern art gallery in central London.

The 17-year-old male, who cannot be named for legal reasons, was arrested on Sunday shortly after the boy, who was visiting London, was found on a fifth floor roof.

His mother was heard by witnesses screaming "Where's my son, where's my son?."

"The injured boy remains in a stable, but critical condition in hospital with his family, who continue to be supported by officers," police said.

The accused teenager is due to appear at Bromley Youth Court later on Tuesday.

The incident led to a lockdown of the museum and visitors were turned away while the building was evacuated.

The Tate Modern, situated in a former power station next to the River Thames, was the most popular attraction in Britain in 2018 with almost six million visitors, according to the Association of Leading Visitor Attractions.