Retail giant Marks & Spencer has restated its reported online sales total because it originally didn’t reveal the breakdown on returns between products bought online and instore.

The food, fashion and furnishings retailer said 2013–14 online sales totalled £649m, £151m lower than the £800m first claimed when it released year to end March 2014 results.

Its changes were also applied to previous years, knocking £500m off total online sales for the past four years.

The restatements don’t affect total group sales, which have always included the impact of returns. However, they didn’t originally break-down the source of sales on items returned to its stores. Now that it has broken that down between stores and online, reported ecommerce sales have been negatively affected.