The Metropolitan Police said he is alleged to have "injected foodstuffs with a number of needles" at three west London shops ？ a Tesco Express, a Little Waitrose and a Sainsbury's Local. They include cooked chicken breast, taken away in bags marked "health hazard".

       Police were called at 7.40pm on Wednesday after a man was reported to be shouting abuse at passers-by.

       Officers took the suspect, earlier seen throwing a pot in a restaurant, into custody, accused of trying to cause public harm or anxiety.

       The shops, all one street, became crime scenes. It is unknown if items were contaminated or what with.

       Council officials warned shoppers to bin items bought from the stores on Wednesday.