Currently Amazon Prime members can get certain items delivered to them on the day they placed their order, at no extra cost.

But Amazon has emailed customers to say they will have to pay £1.99 for same-day delivery if their basket totals less than £20 from 18 September.

The email said: “Same-day delivery can be selected at checkout, but there will be a fee of £1.99 per delivery for orders under £20. The fee for customers who are not Prime members will remain £5.99.”

The new £1.99 same-day delivery charge is on top of the £8.99 a month fee for Amazon Prime.

Monthly Prime membership went up from £7.99 to £8.99 in September last year, while the cost of an annual Prime subscription increased from £79 to £95.

In a statement, Amazon said all orders will be delivered to Prime members with the fastest available free option “by default”.

The Amazon statement said: “Prime members enjoy fast, free one-day delivery on millions of items. We are constantly innovating to deliver a wide selection of great value products at the fastest speeds, and more than a million items are now available for same-day delivery in the UK.

“Prime members can receive same-day deliveries where available for free on select orders over £20, or for £1.99 if the total order is below £20.”

The delivery charge came after Amazon reported record sales during its “Prime Day” promotion in July, which offered discounts on some products for subscribers.