Footage of a man being punched and pushed on to the track at a London Underground station has been released by police.

The victim, aged in his 50s, was attacked at Stockwell station following a short conversation with his assailant.

He was helped back on to the platform by a passer-by before any trains arrived and did not require medical attention.

Det Con Zoe Wornham, of British Transport Police, described it as "an extremely serious incident" and said it was "vitally important" to find his assailant who fled the station after the attack, at about 02:30 BST on Sunday 30 June.