Online customers using the service receive a unique code, which they enter at the lockers to collect their products.
If successful, M&S would be able to use its network of 600-owned and franchised convenience food stores to make it easier for customers to shop its clothing and home offer.
The latter categories have been under severe pressure in recent years, while the food business has gone from strength to strength.
By harnessing the frequency of visits to its grocery stores, M&S could make shopping for clothing and home products a more convenient, and therefore more attractive, proposition.
It mirrors John Lewis’s practice of enabling customers to pick up items ordered from the department store business’s website from click-and-collect points in grocery stablemateWaitrose’s stores.
The trial comes as Morrisons extends a partnership with Amazon to install “hundreds” of Amazon Lockers across its supermarket estate.
The grocer will roll out the lockers by the end of the year, as part of its drive to introduce “popular and useful services” to its larger stores. The move represents the largest collection of Amazon Lockers in the UK.