"Written by William Hughes, director general of the Serious Organised Crime Agency from 2004 to 2010, it is signed by former Metropolitan police commissioners Lords Blair and Imbert, as well as Sir Stephen Lander, the ex-head of MI5, and other eminent figures.
The UK must decide by next summer if it wants to remain fully involved with existing EU justice and police measures or opt out. In their letter to Cameron and Clegg, the signatories say the latter course would have disastrous consequences for the fight against international paedophile gangs and investigations into terrorist networks.
"The growth in cross-border criminal activity within Europe is both an inevitable byproduct of the free movement of goods, services, capital and people under the single market, and a serious policing and security challenge," they say. "Responding to an increasingly international criminal environment requires modern international legal and policing tools, fast and effective cross-border co-operation and the ability to raise standards and share best practice with our closest security partners."
British officers, they say, are at the forefront of shaping effective co-operation. "British law enforcement bodies are now constantly communicating, co-operating and collaborating with EU agencies and other national policing partners in pursuing serious organised criminal and terrorist networks.""
I'm not the biggest fan of recent EU security policy - current policy on Passenger Name Record data and counter-terrorist financial tracking with the US and possibly within the EU is very flawed and without sufficient safeguards - but the value of being a part of this area, and whether or not the UK should opt out, should be much more widely debated. After all if the clamour is for repatriation of powers, surely possible withdrawal from a whole area (and former "pillar") of the EU should attract more comment?