Sainsbury's To You is extending its free mid-week delivery option throughout the autumn in a bid to ease pressure on weekend delivery slots.
The number two e-grocer initiated free delivery slots for orders over£50 on Tuesdays, Wednesdays and Thursdays in the summer and has decided to continue until mid-November.
A spokeswoman said: 'We want to make a seasonal comparison of how it worked in the summer. It makes sense from an operational point of view because the service peaks at the weekend, so it levels it out.'
An e-commerce industry source questioned Sainsbury's motives and claimed it is struggling to achieve sufficient volumes so is trying to entice customers with free delivery.