The Metropolitan Police says it's looking into whether the substance sprayed into the face of an officer may have been ammonia. He was attacked when he stopped a moped rider in Battersea yesterday afternoon.
More top news
A boy has died after he and his friends were attacked while cycling in north London.
Three police officers have been praised for their actions in helping a four-year-old boy who had become stuck on a roof in Newham.
A mother who lost precious photos of her dead infant son when her tablet was stolen is appealing for them to be returned.