Crucial to Sainsbury's grabbing a greater share of the online market will be developing its proposition and post-order service that enables it to lock people into its digital eco-system and sell a wider range of goods.

Speaking at RBTE on Wednesday Robbie Feather, online director at Sainsbury's, highlighted how this was the thinking behind its bid for Home Retail Group: "In the digital space, if we're good at the relationship and post-order then it will give us the opportunity to broaden what we sell. Hence the Argos deal."

This broadening of the offer will enable Sainsbury's to boost its overall online sales that could be restrictive if it sticks to just food, which Feather said is forecasted to only grow from 5.3% penetration to 10% in the UK. However, he added that mobile usage combined with the growth in one-hour delivery options could push this percentage much higher.

"Online grocery shopping is about the weekly shop but if quick delivery takes off then this could bring in convenience food shopping. So it could be greater than the 10% penetration. It opens the door to greater food sales," explained Feather.

He highlighted how the delivery of food opportunity was not being lost on many new entrants into the market in the UK and overseas such as Deliveroo, Uber Eats, and Instacart. Feather admitted that such competition in the market makes it even tougher to achieve profitability from selling online.

For Sainsbury's the big advantage it has is its pick-from-store model, which Feather said sets it apart from much of the competition, including those that operate 'dark stores' dedicated to online orders.

"We're committed to picking from store because you can share overheads [with the stores] and the market is moving towards Click & Collect and one hour delivery for which you need to pick the products close to where the customers are," he suggested.