HE is about to open a secret bunker to combat cybercrime. So Detective Superintendent Stevie Wilson is understandably coy about its capacity.

But his facility - at a confidential location in eastern Scotland - is designed the keep up with the boom in online offending, from child porn to industrial-scale internet bank robbery.

And that means it has to be big. How big? Well, more than mega. Police Scotland measure its memory capacity by the petabyte, that is 10 to the power of 15, a quadrillion bytes. Or 50,000 times the size of the entire archive of this newspaper. Big.

Mr Wilson explains why he needs quite so much computing oomph: the sheer rise of electronic gizmos that police now need to check as part of their investigations.

He said: "Since the outset of Police Scotland we have seen a 47 per cent increase in the number of electronic items for examination, laptops, smartphones, satnavs.

"That is something like 12,000 phones and 1500 computer cases over the course of a year."

These devices are catalogued and warehoused, in huge productions stores. Their contents are copied electronically, everything: text messages, internet browsing histories, downloaded pictures, financial transactions for forensic digital investigation officers to sift through. It's this data that takes up the memory.

A first cybercrime hub - pricetag £1.5m - will start operating in October. Saying where, said Mr Wilson, would only help "the bad guys". Two more are planned, for the west and east, on top of existing capacity inherited from Scotland's old eight territorial forces and the elite Scottish Crime and Drug Enforcement Agency.

The investment may sound modest. But it comes at a time when elsewhere the police are bracing for what Chief Constable Sir Stephen House calls "extreme measures" to balance its budget.

So this cash signals just what a priority internet and electronic offending now is.

Cybercrime, after all, is the big buzz in law enforcement, and not just in Scotland. As official figures for offending falls, many suspect there is a lot of crime online that goes unreported.

Governments, from the EU downwards, are worried. Cyber security is an economic must. Businesses, Mr Wilson reckons, are "increasingly open" about attacks that they may, previously, have failed to highlight. The threat isn't just Scottish. Mr Wilson refers to "countries that fail to cooperate with law enforcement".

He is hinting about places like China and Russia, whose cybercrime industry is thought to be worth more than $2bn. Overall cybercrime losses in the UK were last year estimated at £80bn.

Mr Wilson and his colleagues, however, aren't just investigating stuff that happens somewhere in the ether. The criminals they pursue are flesh and bone. And in Scotland.

Deep in a storage facility full of seized laptops and desktops under an ordinary police station, Mr Wilson explains the scale of the job.

"The vast majority of crimes now have an electronic footprint. From low-level crimes, threats, bullying and extortion online right the way through to serious organised crime and terrorism.

"If you think of how many devices you have compared with five years ago that gives you an idea of the potential growth what we have to look and examine."

What are they looking for? Anything or everything. An aggressive chain of texts or tweets could corroborate a sex offence or domestic violence. A satnav could be used to stock pictures of sex abuse. "Very few cases don't involve electronic evidence," Mr Wilson said.

The new secret facility will increase Police Scotland's capacity to examine such kit by 15-20 per cent from that provided. "There can be backlogs," Mr Wilson acknowledged. "The new hub simply means we can increase the volume of stuff we can process, so you don't have backlogs.

"The sooner you examine something, the sooner somebody gets locked up."

If Mr Wilson is coy about equipment and locations, he is even coyer about his human capacity. Staff can't be pictured, nor their numbers revealed. These, after all, are men and women, two out of three of them civilians, who spend their days, and sometimes nights, grading child porn or sifting through the emails of gangsters.

Staffing has grown under Police Scotland, he says, by 12 per cent. Police are recruiting civilian experts straight from university - Scottish institutions are generating young specialists in cyber security - and keeping them for four-five years before they move to to better-paid private sector jobs.

But the allure of catching sex and other criminals means there are those who want to help. Commercial partners - the firms gradually admitting they have a problem - play an important role. But Police Scotland needs expertise and will be recruiting again. Its next plans? Interns and cyber special constables.

Some of their job isn't for everybody. "Sixty-five percent of the work is in relation to indecent images of children," Mr Wilson explains.

"It's horrendous. But when they identify somebody who has been live abusing and you save that kid, that is some buzz."