Police forces may be snooping on communications data too often, a surveillance watchdog has warned - vowing to investigate. And several local councils are also highlighted for high use of the Regulation of Investigatory Powers Act (Ripa), in a report to parliament.
The warning comes from Sir Anthony May, the Interception of Communications Commissioner, who urged public bodies to consider the impact of their actions on an individual's privacy.
Sir Anthony's first annual report said there were no fewer than 451,253 data requests granted to police forces in 2013, with the highest number obtained by:
* Metropolitan Police - 94,778
* West Midlands - 28,254
* Merseyside - 22.347
* Police Scotland - 19,390
* Greater Manchester - 19,247
Sir Anthony also found that 121 local authorities "have reported never using their powers to acquire communications data", under Ripa.
But 132 councils did use the Act last year - a total of 1,766 times - including:
* Birmingham - 87
* Bromley, in London - 87
* Southampton - 81
* York - 80
* Cheshire West and Cheshire - 75
Sir Anthony said a total of 514,608 requests for communications data were approved, taking into account other public authorities - which "has the feel of being too many".
He said: "It's an inquiry which starts from this raw figure - 514,608. That's a large number and needs looking into."
Such requests attempt to uncover the "who, when and where" of a communication, by phone or email, but not the content.
The retired judge's reported added: "I have accordingly asked our inspectors to take a critical look at the constituents of this bulk, to see if there might be a significant institutional overuse of the part one, chapter two powers.
"This may apply in particular to police forces and law enforcement agencies who between them account for approaching 90% of the bulk."
Civil liberties campaigners called for the government to urgently address the concerns raised in the report - but a Home Office spokesman said communications data was a "crucial tool" in criminal investigations.
And the commissioner cleared the UK intelligence agency GCHQ of breaking the law or any rules - an accusation levelled by US whistleblower Edward Snowden.
In response, Prime Minister David Cameron said the report showed "that public authorities do not engage in indiscriminate random mass intrusion".