As part of its celebrations for the 20th birthday of PlayStation, Sony created a special edition version of the PS4 in the "original gray" colour scheme of the first console and has been selling them worldwide. They sold out completely in the US over a week ago and a very limited amount were remarkably flogged from a pop-up shop in Shoreditch, London last week for just £19.94 each (representing the year the PlayStation was first released).

Now Sony UK is selling the remaining stock, which was taken from the 12,300 units made in total, online but there are several things you need to do to be in with a chance of buying one for the recommended retail price of £399.

The first step is to follow @PlayStationUK and/or @GAMEDigital on Twitter.

Then you need to head to eu.playstation.com/20yearsofcharacters and study the image well. It has a magnifying glass function and this might come in handy as there will be a clue tweeted that relates to something in the picture.

At 4pm today, 5pm on Tuesday, 2pm Wednesday, 8am Thursday and 12pm Friday the tweeted clue will appear on the Twitter accounts above, using the hashtag #20YearsOfCharacters. Solve that clue and head back to the character website. Find the character it relates to, zoom in until a blue cross appears and click it. If right it will take you to a secret website.

READ: Wow, just wow! PS4 20th Anniversary Edition unboxing and hands-on

On that website there will be a form to be filled out and the first 100 to submit theirs with the details required will be emailed by Game with instructions of how to buy the console. This email should arrive within 24 hours.

There will a new allocation of stock and a new clue every day.

Alternatively, if you don't fancy going through all the faff, you could always enter Pocket-lint's competition to grab one of two PS4 20th Anniversary Edition consoles we're giving away to two very lucky readers.

READ: WIN: 2 PS4 20th Anniversary Edition consoles up for grabs