The centre, based in Greenford, West London, will create 800 jobs in the local area, and “significantly” increase the availability of delivery slots for customers in and around the capital.
The third centre will be operated alongside Wincanton, Britain’s largest third-party logistics provider, in a move that marks a 20 year partnership between Waitrose and Wincanton.
The logistics company will help ensure the site is “up and running” for customers “as soon as possible”, with a potential opening date this December.
The group had previously revealed plans to open a second fulfilment centre in May, in an effort to double the number of Waitrose.com slots in London. The latest fulfilment centre marks its effort to meet an increasingly “high demand” in the city.
It comes as the retailer said it has more than doubled the weekly slots that customers can book since the start of the year, and is now processing more than 150,000 orders each week.
James Bailey, executive director for Waitrose, said: “While we’ve already pulled forward our online expansion plans by six months we know there are still lots of people who want to shop online with us and currently can’t.
“This is especially the case in London, where we’ve seen a significant and prolonged surge in demand for our online offer. This new centre will help us better serve the London area with a much broader range of slots.”