Sir, In response to your lead story 'Bogof left behind by rise of unsustainable deals', (The Grocer, 6 November) it's worth pointing out that grocers are already sounding warning bells on the level of promotions. Both Morrisons and Tesco voiced concerns at the IGD Convention in October, when price promotion levels were running as high as 38% at least two months earlier than the Christmas hiatus.

Grocers are increasingly aware that a strategy built on promotional escalation not only erodes value but also brand equity. Of course brands understand that price promotions have a place in the marketing equation. However although they help shift volume, and deliver footfall, they don't build affinity for either brand or retailer in the long term, nor do they build net additional sales.

Both retailers and brands should remember that someone else can always undercut your prices; by contrast, a relationship with customers, built on relevant dialogue through the right channels, is far less open to sabotage.

Crispin Haywood, shopper marketing planning director, OgilvyAction