The FBI-Apple privacy dispute was not an isolated instance but “part of a sustained government effort to exercise novel law enforcement power” over mobile devices, claimed the American Civil Liberties Union.

The US government this week dropped a case against Apple after it found its own way into an iPhone used by one of those involved in a San Bernardino shooting, in what became a high profile debate over privacy versus the demands of law enforcement.

The US government insisted its legal challenge was just about that one case. But the ACLU challenges that assertion with its research.

The government has used 1789 All Writs Act, which gives courts the authority to issue orders necessary to enforce other lawful orders or decisions, in “dozens” of cases against tech companies since 2008, an ACLU study found.

Perhaps unsurprisingly, Google and its Android platform have been a target for law enforcement, in addition to Apple. The ACLU uncovered 63 confirmed cases in which the government applied for an order under the All Writs Act to force Apple or Google to assist in accessing data stored on a mobile device.

It is unclear to what extent the companies co-operated.

The cases predominately arise out of drug-related investigations.

The state-level split is also not surprising. New York and California together account for more than 40 per cent of all requests.