Marks & Spencer has extended its home delivery service.
Customers can order from a range of about 130 M&S food and household items through Deliveroo.
M&S has kept its Simply Food stores and food halls open during the coronavirus pandemic, but the delivery service will make its products available more widely to those confined to their homes.
Deliveroo has added 20 M&S stores in city and town locations - and is providing a more extensive range.
The service, which costs £4.99, is available from 142 M&S outlets across the country.
Rival Sainsbury's recently introduced a one-hour delivery service called Chop Chop, which allows customers to order a top-up shop of up to 20 items. It too charges a £4.99 delivery fee.
M&S is one of the few big food retailers without its own internet-based delivery service. This has hampered the chain as it struggles with the decline of bricks-and-mortar High Street stores and the move to online shopping. It is planning to launch a new delivery service with Ocado in four months' time.
The coronavirus outbreak has accelerated this trend. Online sales now account for 10.2% of the grocery market, up from 7.4% before the pandemic, according to latest data from Kantar.
Retail analyst Richard Hyman said M&S's arrangement with Deliveroo was a "pragmatic move" that felt more tactical than strategic.
"It sells niche products which have often been used as a top-up to the main food shop for treats," he told the BBC.
"In this constrained period, if people are going to have to queue to get into the shop, they may well jettison their top-up."
Mr Hyman said bigger M&S stores were likely to be "right at the heart of the country's population centres, where everything else is shut, and that will have impacted footfall".
Dave Gill, national officer for the shopworkers' union, Usdaw, said the company needed to be mindful of its workforce: "We understand that retailers are having to introduce new working practices and services to help keep our communities fed during the Coronavirus emergency.
"These innovations are welcome, as we all try adapt to the 'new normal', but they must be done safely and that is best achieved when working with a trade union."
He pointed out that Marks and Spencer have a tradition of not engaging with unions.
M&S announced last year that it would go into partnership with Ocado from September this year, replacing the online grocer's existing deal with Waitrose.
Under the deal, M&S is buying a 50% share of Ocado's retail business for £750m.
Ocado will also continue to supply its own-label products and big-name branded goods.