Leading retailers face higher staff costs due to this year’s extra bank holiday for the Royal Wedding.

One grocery source told Retail Week he expected extra staff costs to be at least £40m at supermarkets alone as a result of higher rates paid to staff who work that day.

Retailers are divided over whether the higher cost will be covered by increased sales. The nuptials are expected to boost the retail sector by £400m altogether and grocers are expected to take £360m of that.

Some retailers will treat the day that Prince William and Kate Middleton tie the knot, April 29, as a standard bank holiday, for which they pay staff extra. Retailers taking that approach are understood to include Asda, Tesco and jewellery giant Signet. Others are offering staff a day in lieu. Electricals retailer Comet does not pay more on bank holidays but staff will be given an extra day off. It will also be a regular working day at Argos-owner Home Retail Group, but staff may take the day off if it fits with rotas.

One big fashion retailer said its store staff working the bank holiday would be given a day in lieu.

Some retailers are optimistic that they will benefit from the extra bank holiday, despite the extra costs that might be incurred.

Bank holidays are usually busy for furniture and DIY retailers.

Carpetright group commercial director Martin Harris said: “We don’t look at bank holidays with dread. It’s a good period for us.”