A mother decides to go to a local supermarket to steal a tin of beans for her hungry children. She leaves he house with no money, takes a basket, goes to the supermarket aisle, picks up the tin of beans, and places the tin In the basket. She then moves the tin from her basket to her coat pocket. She then drops he basket and walks past the till, making no attempt to pay. She is then stopped by the security guard outside the store.At what point has the mother committed the offence of theft?