As the US depletes its stock of IPv4 addresses, questions will be raised about the UK and whether it will reach the same position.

Since every device that is connected to the internet requires a unique IP, depletion means internet service providers in the US will now have to trade or lease addresses to allow new customers to connect to the internet, until another method of allocating addresses is achieved.

"The UK is not technically out yet but it is running on fumes," says Dr. Tim Chown of Southampton University, Chair of the UK IPv6 Council.

Currently IPv4 addresses are being rationed by Regional Internet Registry for Europe (RIPE) and the most that can be provided to a single applicant is a /22, which is 1024 addresses.

"To all intents and purposes the rationing means access to significant amounts of address space is very limited," says Chown.

While some ISPs have been using an alternative IPv4 sharing technique called Carrier Grade NAT (CGN), by which an IPv4 address is assigned to a network or site and then shared between end-points, the real solution will be the new standard, IPv6. While IPv4 offers 4.3 billion addresses, IPv6 offers around 340 undecillion addresses.

He says: "if we want to see the internet continue to grow, and not have networks and devices hidden behind two layers of NAT, making end to end communication complex (and need to use some 3rd party with a global address), then IPv6 is the only way to go."

So how are the UK ISPs doing in the transition? While smaller providers such as AAISP, Clara.net, Entanet, Exa Networks, Goscomb Technologies, IDNet, Webtapestry, have moved, major providers like BT and Sky have been slow.

BT this week announced that it would be rolling out IPv6 to 100 percent of customers by December 2016, while Sky has already rolled it out to one million customers.

It’s about time. According to Apnic, the UK is 26th in the world for IPv6 deployment, with only around 4 percent of the population able to use IPv6.

This is behind the US at 26 percent and Germany at 25 percent and Belgium with 44 percent. The world leader is St. Helens, with 100 percent – although this may be because its population is only 3960.

"From the national point of view, the UK government should be seeking to make sure Britain is a good place to do IT; we should be higher on that list," says Chown.

"The government’s position has been to let the market decide; in other markets the government has encouraged deployment.

"On the government side, it would be useful if Ofcom put out more positive messages about IPv6, or at least not put out negative messages, and the DCMS should ensure IPv6 features in future broadband – good broadband is not just about speed – no point being fast if no one can reach you as you have no addresses for your equipment."

As for businesses, Chown suggests that organisations should be getting prepared for IPv6 now.

"Deploying IPv6 in an orderly fashion can take 2-3 years, so given the current position of IPv4, they should really be starting the process now, if they haven’t already.

"Include capability in routine refreshes, with a view to turning it on as fuller overall capability is achieved."