Who is top of the supermarket loyalty league?

Sarah Coles
shopping trolley
shopping trolley

Which of the big supermarkets has taken the title as the one that inspires most loyalty? Surely Tesco must be in with a shout - given that it commands 30% of the nation's supermarket shopping. Or how about Asda, the nation's number two supermarket - serving over 18 million of us? Or Waitrose, Britain's fastest-growing supermarket (with sales up 4.8% this year)?

No... they were all beaten by a budget superstar.