Amazon’s sales and profits jumped last year, helped by an uptick in demand for Prime.

Profits hit $3bn in 2017, up from $2.4bn the previous year.

Full-year revenues stood at $177.9bn, up 31%.

The retail behemoth saw a record 38% rise in fourth-quarter sales, which topped $60.5bn.

This performance is in stark contrast to much of the retail industry as many businesses suffered flat or falling sales over the festive period.

Its fourth-quarter profits more than doubled, hitting $1.9bn, due to a tax benefit of around $789m, related to new US tax laws.

Amazon emphasised the role of Prime in its success, saying more members joined the scheme last year than in any previous year.

It sent five billion items worldwide via Prime during 2017, with four million people signing up in a single week during the golden quarter.

Founder and chief executive Jeff Bezos highlighted the success of Alexa, Amazon’s own-brand voice-activated technology.

He said: “Our 2017 projections for Alexa were very optimistic, and we far exceeded them. We don’t see positive surprises of this magnitude very often – expect us to double down.”