Sir: I am writing in response to your piece on The Co-op investing £100m in price reductions (‘Co-op targets Express/Local with price cuts,’ 26 April, p6). Promotions - such as half-price, lunch deals and link-saves - and their effectiveness have long been a topic of hot debate; an entire industry exists around their planning and evaluation.

However, moves by the big supermarkets to implement every day low prices indicate a fundamental shift in the future of promotions. The conventional wisdom is that cutting promotions and moving to EDLP results in a drab in-store experience devoid of ‘theatre’. Yet Aldi - the country’s fastest-growing grocer - offers very few promotions and, at the risk of understatement, this doesn’t seem to be doing it any harm. Some 45% of the big four’s sales are currently the subject of some form of promotion. For Aldi, the equivalent figure is just 3% and falling.

A consistent EDLP and low-cost approach presents many advantages. Sales are predictable when not subject to wild promotional swings, facilitating consistent ordering patterns and dramatically lowering inventory across the supply chain. There is also a benefit to shoppers that EDLP is transparent and reliable, cutting through the often confusing world of promotions.

The Co-operative has adopted ‘Fair & Square’ pricing, Asda now has ‘Price Lock’, and Tesco proclaims ‘Prices down and staying down’. The language used is very long-termist - it looks like EDLP is here to stay.

Edward Garner, director, Kantar Worldpanel