A man who appeared to try to take a woman's cashback at a supermarket before headbutting her partner is wanted by police in Bexley.

Police are investigating a theft and suspected actual bodily harm at ASDA in Bexleyheath Broadway.

A woman forgot to collect her cashback at the self service checkout and police say the suspect picked it up after she left. 

As the suspect went to leave the store the woman's partner confronted him. The suspect then headbutted the victim and left with the cash.

Police are asking anyone with information to contact Crimestoppers.