Source: Marks & Spencer

M&S has been working to create branded products of “near-identical specification” to the Waitrose lines currently listed on the site

Ocado customers have found M&S products in their food deliveries weeks ahead of the online grocer’s switchover from Waitrose on 1 September.

The M&S branded items arrived in customer orders as substitutions for out-of-stock Waitrose goods due to a “system error”, Ocado said.

M&S – which formed a joint venture with Ocado last year – has been working for months to create branded products of “near-identical specification” to the Waitrose lines currently listed on the site. A total of 6,000 M&S products will eventually be available, replacing the 4,000 Waitrose products currently stocked.

But late last month, some of the replacements found their way into customer orders.

“Due to a system error, a very small number of M&S products were substituted for out-of-stock, equivalent products, and incorrectly delivered to Ocado customers at the end of July,” a spokeswoman for Ocado said.

“This was swiftly corrected and we notified affected customers who were issued with a refund,” she added.

In a bid to stop Waitrose fans leaving Ocado next month, M&S said it has “replaced as many Waitrose products as possible with an existing M&S product, or a new one that is being specifically developed”. All M&S replacements will be the same or better value than their equivalent Waitrose item, notably on KVIs. M&S Food MD Stuart Machin said hundreds of items “are the most competitively priced in recent history”.

M&S products are already listed on and can be added to baskets for those with delivery slots on or after the switchover date. But customers seeking to buy M&S food online could be left disappointed, with Ocado’s capacity constraints limiting how many homes it can serve.

Both M&S and Waitrose have been ramping up multichannel marketing campaigns in recent days to win Ocado customers. Waitrose products make up around 10% of Ocado’s SKUs but almost a quarter of its grocery sales.