Say goodbye to lengthy checkout queues and unidentified items in the bagging area: at the new till-less Amazon Fresh stores you can pick up your groceries and leave without physically paying at all. So what's the catch?
Amazon's new convenience stores, which have so far opened in west and north-west London (Ealing, Wembley and White City) use in-store cameras and 'Just Walk Out' technology to track what you've picked up while shopping. Your Amazon account is then billed after you leave the store.
A contactless shopping experience might sound appealing - but does this convenience come at a higher cost to your bank account? And do Amazon Fresh stores offer a crystal-ball glimpse into the future of grocery shopping, or are they only a soon-to-fizzle fad?
Here, you can watch our reporter's video diary of his visit to the Ealing branch of Amazon Fresh, and find out from behavioural experts how till-less shopping could change the way we shop.
Shopping at an Amazon Fresh store is an entirely different experience from visiting your local Tesco or Sainsbury's.
To get into the store you need to create an Amazon account (if you haven't got one already), download the Amazon app, choose the account or card you want your shopping to be billed to and generate a unique QR code.
Once you've scanned the QR code at the store entrance, you're free to walk in and start shopping, using your own bag or one of Amazon's free paper bags.
When you're ready, simply leave the store and wait for your receipt to come through.
Curious to see it for yourself? Our video reporter Harry Kind filmed his experience of the Ealing store and tested out how well the tech really works:
In response to the red onion that Harry wasn't charged for, Amazon told us: 'Just Walk Out technology is highly accurate. At Amazon, we spend the vast majority of our time thinking about improving the experience for the 99.9% of well-intentioned customers.'
Harry received a receipt via email around 30 minutes after leaving the store, but don't panic if you're waiting longer than this: Amazon told us that customers will be emailed receipts within a few hours of their store visit.
Your debit or credit account, depending on the payment method you selected, will then be billed accordingly.
The Amazon Fresh store we visited sells mostly food and some everyday essentials such as personal hygiene products and laundry detergent.
The store stocks a lower proportion of own-label products on its shelves compared with other supermarkets, according to ESA Retail.
These own-label brands include 'Amazon Fresh' and 'By Amazon', as well as the 'Our Selection' premium sub-brand range. Amazon Fresh stores also sell Morrisons-branded products in line with its partnered delivery service.
There's a range of promotions on offer, including multibuys, meal deals and 'night in' options.
But - as is often the case with smaller convenience stores - you could end up paying more than if you visited a bigger supermarket.
ESA Retail carried out a basket price comparison with other bigger supermarket stores, including Aldi, Asda, Lidl, Morrisons, Sainsbury's and Tesco.
The full basket of 21 items came in at £31.79 at Amazon Fresh - more expensive than any of the other six retailers despite the fact smaller pack sizes had to be selected for a number of items on the list.
It's worth thinking about whether you want convenience or cheaper prices when deciding where to get your groceries.
If your receipt isn't right, you can request a self-refund through the app or contact customer services.
And if you're unhappy with an item or it's faulty, you can request a refund within 30 days of purchase.
You don't have to physically return any items purchased at an Amazon store, you can simply request a refund through your account.
If your account is fraudulently used in a store, Amazon says it will handle this in accordance with store policies and you should contact its customer service team.
It's thought that more Amazon Fresh stores will open across the Greater London area - so how might till-less tech change what we buy and how much we spend? And is checkout-free shopping likely to become the new norm across the UK?
We spoke to Christian Eichert, lecturer in marketing and consumer behaviour at Goldsmiths University, and Irene Scopelliti, Professor of marketing and behavioural science at Cass Business School, to find out.
Christian believes the speed and convenience of till-less stores could stop us from really considering whether we need the items we're buying.
'Speeding up the shopping experience prevents people from deliberate consideration,' he says. 'An act of decision-making takes cognitive effort. If you're just picking things up and don't have the time when you queue at the till to think about whether it's what you need or can afford, then Amazon is likely the winner of this.'
It's worth bearing this in mind if you do visit one of the stores: do you really need everything you've picked up? And could you find cheaper options elsewhere?
Irene thinks people may enjoy the 'false sense of anonymity' while shopping in the stores, which could make buying personal products a less embarrassing experience than if you were using a checkout.
We asked Christian and Irene whether the ease of payment impacts shoppers' behaviour.Christian notes how the 'instant gratification' of picking up items at an Amazon Fresh store and receiving the bill later is similar to what you might experience when shopping with a
These schemes - such as Clearpay, Klarna and Laybuy - allow you to order items and pay for them at a later date or in instalments.
'Everything is about immediacy,' Christian says. 'You get the product first, it's an instant psychological gratification, and then you temporarily displace the painful exercise of paying until you get the receipt later, and then later still when you see the charge on your bank account.'
Irene believes this move away from making instant, physical payments could lead to less considered purchases.
'The act of paying is very concrete and tangible, and therefore more painful, so consumers tend to be more thoughtful with their purchases when paying in cash,' Irene explains. 'Eliminating the checkout procedure is likely to further reduce the pain of paying, and may indeed increase the likelihood of making mindless purchases.'
Both Irene and Christian recognise that Amazon Fresh stores' futuristic tech could deter certain groups of consumers.
'Barriers to the store, such as having compatible smartphones and the Amazon app or being comfortable with electronic payments, may make it a less preferred option for consumers who need more support for making their purchases,' Irene says.
Till-less technology could also create generational divides.
'The shop appeals to innovators, early-adopters, to a young, urban, educated crowd of people who might be comfortable with sharing their personal data,' Christian says. 'Would my grandma use these stores? I don't think so. Would my students? I think they'd embrace it.'
But Irene believes till-less shopping could well be a more user-friendly experience, requiring less input from shoppers than 'faulty self-checkout tills' that can slow down your shopping experience.
If rolled out more widely across the UK, the move away from cash could also seriously reduce shopping options for people who prefer or need to use cash.
Which?'s Freedom to Pay campaign is demanding that the government changes the law to guarantee that access to cash is protected for those who need it.
For Irene, the novelty factor of the stores is unlikely to secure a long-term customer base.
'Novelty is transient and wears off quickly,' she says. 'I suspect the novelty factor will bring visitors to the store but is unlikely to drive their loyalty.'
But she believes the tech could - eventually - become the new norm for grocery shopping.
'As with many other innovations in the retail sector, I believe it may sooner or later be adopted by other retailers as well,' she said. 'Think about self-checkout, which is now offered by virtually all retailers.'
She notes, though, that the technology still has some way to go: 'Similar to what we see with self-driving cars, this technology is still under development and being tested. It will take some time before it becomes mainstream.'
But Christian believes other more traditional supermarkets will always be on the back foot when it comes to adopting similar technologies.
'Amazon can do software, hardware, networks, warehouses and logistics,' he told us. 'It's not a battle between equals because, at heart, Amazon is a technology company.'
So don't go leaving your purse or wallet at home just yet - it sounds like checkouts won't be disappearing from your local supermarket any time soon.