The definition of what makes a convenience store often depends on the outlook of the person asking the question. For a local retailer, stocking milk, bread and a few essential grocery items is often enough. For a major grocery supplier, 3,000 square feet of gleaming store, well planogrammed and merchandised is often a starting point. I like Nigel Mills' definition. If most of your shoppers pick up a basket when they walk in, you have a convenience store, he says. So news that Waitrose is to open hundreds of c-stores around the UK may be a concern if your shoppers are picking up baskets. It could be that your shoppers are the ones it is targeting. However, this week's stock market update by Marks & Spencer chief executive Stuart Rose shows that he believes Waitrose is after his shoppers. M&S has unveiled advertisements showing that its wise buys are cheaper than Waitrose's essentials. If shoppers think M&S is more expensive, it is not true, says Sir Stuart. ...