Amazon is set to launch a new global shopping day promising more deals than Black Friday - but only for consumers who have signed up to its annual subscription service.

The inaugural Prime Day on July 15 will give shoppers in the UK more than double the number of deals Amazon offered on Black Friday last year, the retail giant has promised.

But shoppers will have to be members of the Amazon Prime subscription service that costs £79 a year - or £59 under a special deal to tempt consumers ahead of the event.

It is the latest in Amazon's bid to turn its customers into paid-up members of the service.

Last week it introduced one-hour delivery for £6.99 on more than 10,000 items to Prime members in specific postcodes in London, with the promise the service would be rolled out across the capital and additional cities.

From midnight on Prime Day, shoppers will see thousands of limited-time Lightning Deals, six "deals of the day" and will receive unlimited fast and free delivery.

Prime, which started as a one-day delivery benefit in 2007, now has "millions" of members in the UK, Amazon said.

Amazon UK managing director Christopher North said : "Prime Day is the latest benefit for Prime members and you can expect us to add further benefits and features to this great service over time."

Worldwide paid membership to Prime grew 53% last year, the retailer said.