This is the heroic moment a local scrambles down a tower block to save a boy dangling from a window over a dizzying 100ft drop onto the pavement.

Dramatic footage shows a boy hanging by his shirt from a seventh-storey security grille in Wuzhou, Guangxi, China, on December 12.

The video captures optimistic well-wishers stretching out a thin duvet to catch the lad, who looks no older than five, if he falls.

But within moments, a neighbour climbs out of a window on the floor above and clambers down the sheer face of the building using sills and an air conditioning unit as toeholds.

Then, he inches along a narrow ledge until he reaches the boy and carefully unhooks him, pushing him back through the window to safety as the clip ends.