…and the pounds will look after themselves. So goes the old saying. The nation of shopkeepers that Napoleon had in mind dealt more at the pence end of the spectrum (rather than the pounds and shillings end). The average spend in an average convenience store is still only a few quid, so you need to watch those pennies.

Ian Phipps, who runs Phipps Newsagents at Westhoughton in Bolton, is certainly doing so.

He took part in a Twix on-pack promotion and he told me that since the promotion lost him money, he will no longer stock Mars, Twix, Snickers or Maltesers.

He writes: “Twix, Mars and Snickers sell at 51p, which equals a profit of 10p per bar including VAT. An on-pack promotion gave one in six a free bar with a voucher. The retailer sends off the voucher by second class post and waits a month for a cheque to arrive.”

His cheque from coupon redemption company RMI was for the princely sum of 86p, which included 32p for postage and 3p for handling.

He says postage cost a minimum of 50p, the envelope 5p and the couple of minutes work (worked out at minimum wage level) was 18p, adding up to 73p.

The bar at cost all told was £1.24, the credit given was 86p and the difference, 38p, was what he actually lost.

I sent Ian’s figures to Mars Chocolate UK, and Bep Dhaliwal, trade communications manager, says: “We were sorry to read Ian’s comments and are investigating the matter fully, working closely with RMI. We will also be contacting Ian directly to address his concerns. We would like to reassure Ian, and all retailers, that the postage rate has already been increased following an initial miscalculation.”

Other retailers taking part in the promotions can therefore thank Ian for sweetening up the incentive.