The mobile data spectrum already earmarked for 4G services in the UK will not be enough to head off a serious “capacity crunch” in the next decade, telecoms regulator Ofcom has predicted.

The Organisation’s Infrastructure Report update sets out the scale of demands being loaded on to a data-carrying system that must nevertheless cope with a finite amount of radio spectrum.

In the last year, the volume of mobile data being generated by the UK’s mobile networks has more than doubled from 9 million Gigabytes to 20 million with Ofcom estimating that demand for mobile data will soar 80-fold by 2030.

The average mobile customer now downloaded 245MB of data in a year, a growth that won’t be satisfied by the spectrum due to be freed up to serve 4G services.

“Within the coming months we will hold the UK’s largest-ever auction of mobile spectrum for 4G. However, that may not be enough to meet consumers’ future data demands, which is why we are already making significant efforts to prepare to go beyond 4G,” said Ofcom chief executive, Ed Richards.

“Our plans are designed to avoid a capacity crunch, ensuring that the UK’s mobile infrastructure can continue to support the inescapable growth in consumer demand and economic growth more generally.”

Ofcom’s proposes to find the spectrum for future services – “5G in telecoms parlance – by moving into the 700MHz frequencies currently used by digital TV.

It’s not clear whether this would mean another re-tuning of TV set-top boxes will be required although Ofcom’s optimistic pronouncement is that it won’t within the short to medium term.

According to Ofcom, other much-needed capacity could also be provided by public Wi-Fi, still hugely under-used by consumers tethered to the 3G and emerging 4G services offered by operators.

If true, the number and range of access points will have to increase from the modest 16,000 Ofcom reckons are currently available in the UK.

Not everyone is convinced as Ofcom that mobile data is on as dramatic a collision course with available frequencies.

“With the rise in popularity of high spec smartphones and portable tablets it was not unexpected to see that mobile data usage has more than doubled in the last 12 months. However, as ownership of these devices reaches saturation point we may see mobile usage growing less rapidly,” said editor, Andrew Ferguson.

Given that mobile data was also considerably more expensive than fixed services, it was also likely that operators would stem some demand by through pricing.

Meanwhile, fixed services continue to outstrip mobile services in terms of speed and pricing; the average broadband speed was now 12.7Mbits/s, up from only 7.5Mbits/s a year ago.