Waitrose has said it can more than double its “online capacity” in London with the opening of another e-commerce grocery depot in the city.

The UK retailer has plans for a site in Coulsdon in south London, which, it said, will open next autumn.

The depot will despatch up to twice as many orders a week as its current dotcom fulfilment centre in Acton, in the west of London.

Waitrose said the new facility would “build upon the traditional dark store model” at Acton. That site has aisles set out like a Waitrose branch from which staff pick items for orders. Waitrose said the new facility will create 500 jobs.

“Demand from Waitrose.com shoppers in the capital has soared over the last year. Our dotcom fulfilment centre in Acton will reach capacity in 2014, and we have been looking for the right location for a second for some time,” Waitrose retail director Rob Collins said. “The dotcom fulfilment centre in Coulsdon provides the perfect, purpose-built site for us to take what we have learnt from Acton and step our online operation up a gear.”

Sales from within the M25 motorway that orbits London are becoming a more important of revenue from waitrose.com. The retailer said its e-commerce sales within that region tripled last year to account for 20% of all waitrose.com sales.

Waitrose launched online delivery within the M25 in 2011 after the end of a non-competition clause with partner Ocado.

Waitrose had sold its own-label lines through Ocado in the region as well as operating its own service in the rest of the UK but the terms of their agreement meant the grocer could not offer home delivery in and around the UK capital.

In May, Ocado teamed up with Morrisons in a technology and distribution deal that will see the online firm help the supermarket chain set up its home delivery service next year.

Before the deal was announced, Waitrose MD Mark Price had expressed concern at the prospect of Ocado working with another UK retailer in the fast-growing online channel.

Announcing the deal, Ocado CEO Tim Steiner insisted the deal with Morrisons would not affect Ocado’s existing partnership with Waitrose.

However, some analysts believe Waitrose could look to enact a break clause in its current deal with Ocado. That agreement, which runs until 2020, includes a clause that could allow Waitrose to walk away in 2017.