The cost of storing the data is estimated to about £175m over the next 10 years.
He spent his time retrieving hard disks from dumps and painstakingly storing the data of conversations and communications.
Unlike Microsoft's products, which reside on PCs and corporate networks, Google's will be delivered as services accessible over the Internet, with Google storing the data.
But Apple acknowledged that it had made mistakes, which it attributed to programming errors, in storing the data for a long time, keeping the file unencrypted and storing the data even when users had chosen to turn off location services.
The Home Office said "strict safeguards" would include a 12-month limit on storing the data and measures to protect the data from unauthorised access or disclosure.
Alexander said he would be comfortable storing the data somewhere else or requiring more reports on how the data is used, but that the NSA's surveillance work should not end.
Really, big data has moved on from the initial stage – where the challenge was about storing the data – and has moved onto the next, which is all about the insights companies can obtain from the data.
"The problem with the consent model is that users don't read the terms and it's hard to comprehend what the effect of storing the data over time will be," Mr. Hoofnagle said.
That does not include the price of upgrades to computers and servers that police departments would probably have to undertake in order to process the enormous quantities of data the cameras produce, or the cost of redacting the videos for potential public disclosure or litigation, or the cost of storing the data.
Other challenges for the field include storing the data.
We're not storing the data, just doing some cacheing.
