Research in Motion's Blackberry email service is too important to be shut down by the US District Court, the company claimed in papers filed in its legal battle with NTP this week.

RIM's pitch to Judge James R. Spencer, who is presiding over its fight with NTP, is that its service has become a cornerstone of the US economy thanks to its use by government agencies and Wall Street workers. Blackberry is part of the nation's "critical infrastructure" and is essential to the US' "economic security", RIM pleaded.

Limiting the service to key workers wouldn't work either, it claimed. "It would be extraordinarily impractical, if not impossible, to devise and administer an injunction that would protect government and private sector BlackBerry users who would be, or should be, excluded from an injunction,'' RIM said in its filing.

NTP, of course, wants RIM - which has already been found by both the District Court and US Court of Appeals - to have infringed NTP's intellectual property, to face the consequences of its action. It responded to RIM's statement by pointing out that its rival "must simply turn those accounts off in the same fashion as when a customer fails to pay its bill", Bloomberg reports.

No one, said NTP, has any right to complain if Blackberry is shut down: the prospect of such a suspension has been widely discussed for more than two years - more than enough time to put in place contingency plans.

RIM claims it has a workaround to avoid a shut-down order, and it finally came clean on why it's holding back on just releasing the fix and turning its back on the NTP threat. The solution would force users to install new software on both servers and Blackberry handhelds, it said in its court filing. ®