Brexiteers are fearmongering about security after we leave the EU – but there are some reasons for concern

National security is a matter of the gravest importance and should not become a political football when it comes to Brexit, a number of public figures sagely declared at the time of the referendum. But that is exactly what it has become, with the emotive accusations and recriminations that have characterised the arguments about leaving the European Union.

In a much-trailed speech Ben Wallace, the security minister, today stated that the deal negotiated by Theresa May will help the UK “build the broadest and most comprehensive security relationship the EU has ever had with another country”. Failure by MPs to approve the deal, he warned, will effectively put public safety at peril.

Hardline Brexiters have predictably dismissed Wallace’s pronouncement as part of the supposed “Project Fear”. Some have gone even further, claiming that May’s deal is an act of surrender, jeopardising national security, and indeed that of the West, while undermining Britain’s solidarity with English-speaking nations. The agreement, they hold, is nothing but abject surrender of sovereignty.

An example of this view came in a letter to The Sun written by the former head of MI6, Sir Richard Dearlove, the former Royal Marine Major General Julian Thompson, and the former chancellor Nigel Lawson (who recently applied for French residency). They hold that the deal “puts at risk the fundamental Anglosphere alliances, specifically the vital Five Eyes Alliance and thereby threatens western security... The ‘deal’ surrenders British national security by subordinating UK defence forces to Military EU control and compromising UK intelligence capabilities.

“No risks are greater than the Withdrawal Agreement’s terms of surrender. The people voted to take back control of our sovereignty, not for a colonial status. Mrs May has broken trust with the British people as she has lost the trust of so many of her ministers.”

The origins of the “Five Eyes” states – the UK, the US, Canada, Australia and New Zealand – go back to the Atlantic Charter, issued in August 1941. Some aspects of intelligence sharing was extended to include Norway, in 1952 and West Germany, in 1955, as “third parties”. Also in 1955, under a new UK-US Agreement, it was decided that the Five Eyes term would be a shorthand for an “AUS/CAN/NZ/UK/US EYES ONLY” classification level.

The UK did not stop being a member of Five Eyes when it joined, on its third application, what was then European Economic Community in 1973 or when it then became the EU. There is no reason whatsoever why its position in Five Eyes should be at risk now that it is leaving the EU.

It should be noted at this point that, in recent times, there has been concern in some western intelligence services regarding information sharing, not with Western European states but with the US. Not American intelligence and security agencies per se, but rather there is a worry that some sensitive material might get into the hands of people in the Trump coterie, as more and more details emerge about their links to Russia and other foreign states. Special counsel Robert Mueller has indicted 32 people so far in his investigation into whether Trump was effectively Moscow’s candidate in the US presidential election. The indictees include former national security advisor, Michael Flynn, and former campaign chairman Paul Manafort.

The supposed “subordination” to the EU has long been an accusation made by Brexiters. At present Britain participates in the Common Security and Defence Policy (CSDP) which was set up by the UK and France after the St Malo declaration in 1998 in an attempt to address peacekeeping failures in the Balkan wars. The missions so far have included enforcing the Dayton Agreement in Bosnia; anti-piracy patrols off the Horn of Africa; and controlling people-trafficking in the Mediterranean. Member states choose which, if any, missions they want to join.

The idea of a “true European army” was mooted recently by French president Emmanuel Macron to ensure that Europe does not “become a plaything of great powers”. Macron raised the issue in reaction to Donald Trump continually criticising Nato and the EU while refusing to condemn Vladimir Putin for his actions, sabre-rattling in eastern Europe, and the spread of Chinese military hegemony through naval bases in the Pacific and Indian Oceans.

Successive governments in London have repeatedly stressed that the cornerstone of UK security policy is Nato, not any other European institution. This was reiterated by defence secretary Gavin Williamson just this week and there is no reason why it should change in the future. In any event, Macron’s “true European army” is not much more than a concept at the moment and would never actually supersede Nato.

So, many of the charges on defence and security made by the Brexiters on “surrendering sovereignty” and “threatening western security” in the May deal do not stand up to scrutiny. But what about the claim made by Ben Wallace that it would solve all security problems in leaving the EU? Nothing has been presented, so far, to prove that is the case.

Britain wants to keep all existing security arrangements and the EU acknowledges that it is in its interest to cooperate on the matter. But it is not at all clear whether the UK will be able to access Brussels-run databases on criminal records, DNA and fingerprint records after the transition period.

There will have to be a new security agreement for this to happen – and that is unlikely to be easy to achieve, due to a number of problems. For instance, some countries such as Germany are barred by their constitutions from sharing security information with non-EU states.

It is also now clear that the UK will no longer have access to military-grade signals from the EU’s Galileo system after Brexit. Renegotiating access has been such a difficult process that the British government is looking towards building an alternative system at a cost of up to £5bn. But even that would involve negotiating signal space with other countries already operating navigation systems – the US, Russia, China, Japan and India.

Before the referendum took place Sir John Sawyers, the former MI6 chief, and Lord Evans, a former head of MI5, pointed out that the EU was essential for sharing data.

The two chiefs wanted to stress that “intelligence work today relies on the lawful and accountable use of large data-sets to reveal the associations and activities of terrorists and cyber-attackers. The terms on which we exchange data with other European countries are set by agreement within the EU.” Sir John and Lord Evan stated a vote to leave “would create instability, worsening the existing economic difficulties, the migration crisis and a resurgent Russia”.

The referendum took place, with the result that this happened, and these problems are now more pressing than ever .There is a long way to go before the damage is adequately limited through painstaking negotiation. That is the reality we face behind the rumbling rhetoric of Brexit.