The world is about to run out of the internet addresses that allow computers to identify each other and communicate, the man who invented the system has told The Times.

Vint Cerf, the “father of the internet” and one of the world’s leading computer scientists, said that businesses and consumers needed to act now to switch to the next generation of net addresses. Unless preparations were made now, he said, some computers might not be able to go online and the connectivity of the internet might be damaged.

Mr Cerf said that internet service providers in particular needed to prepare and that time was running out for a smooth transition.

Every computer and online device is assigned a unique IP address, but the pool of unallocated numbers is about to dry up. “This is like the internet running out of telephone numbers and with no new numbers, you can’t have more subscribers,” he said.

When Mr Cerf and others founded the internet system in 1977, he set in place “internet protocol version four” (IPv4) which provided 4.2 billion addresses. With the number of internet-enabled devices, particularly mobile phones, soaring, less than 14 per cent of those addresses remain vacant. It is estimated that IPv4 addresses, each of which is a series of 32 binary digits, will run out in 2010 and possibly as early as next year.

A new system, called IPv6, has been ready for implementation for more than a decade. Under IPv6, each address has 128 bits and so provides 340 trillion, trillion, trillion different addresses — that is 340,000,000,000,000,000,000,000,000,000,000,000,000. It is assumed that this will meet humanity’s needs for decades to come.

The two protocol systems will run in tandem and IPv4 addresses will still work as normal. But if the IPv6 is not widely adopted, then those using it may find themselves unable to connect across the whole internet. Mr Cerf said the rise of the “internet of things” where ordinary objects such as light switches, radiators and cars are connected to the net has accelerated the rate at which the IP addresses are being used up.

He said he had been speaking to ISPs, including AT&T and Verizon in the United States and BT, the biggest ISP in the UK. He said the bulk of companies had no idea about IPv6 and the ISPs were not informing them. “They are persisting in the ‘nobody is asking for this’ mentality,” he said "They are not valuing business continuity as they should.

He said consumers needed to be aware of IPv6 and to start checking that the products they buy are IPv6 compatible.

Most software companies such as Microsoft and many hardware companies are already making their products IPv6 ready.

It is thought that, properly handled, the effect of the introduction of IPv6 on consumers will be minimal, although eventually home routers may have to be upgraded or swapped so they can use the longer addresses.

Gars Telecom Company obtained the new format addresses in May, 2008.