The UK may need to cede some sovereignty to Europe in the fight against terrorism, argues Mark Cotter, Q.C.

Acts of terrorism are occurring all too frequently in Europe, making co-operation on security with the EU vital.

The government’s recent policy paper on the implications of Brexit for security suggests that Britain enter into a treaty with the bloc, but the paper is light on detail as to how this will be achieved.

David Davis, the secretary of state for exiting the EU, has acknowledged that the UK together with the other member states has developed some of the world’s most sophisticated crime-fighting systems. He said that “cross-border co-operation is absolutely crucial if we’re to keep our citizens safe and bring criminals to justice”. A review of that co-operation found that those tasked with drafting this treaty will have a complex task ahead of them.

The UK would wish to retain its membership of Europol, which is currently led by a British director. It would need to replicate the European arrest warrant system, which allows for speedy surrender of suspects between European states.

It is vital that Britain continues to participate in the European passenger name records database. This was developed by the UK to identify terror and serious crime suspects travelling across Europe. After a delayed accession to the Schengen Information System II, British law enforcement agencies would no doubt wish to retain the alerts that it provides about sex offenders and other criminal suspects. Last year there were 9,500 such alerts.

After the Charlie Hebdo attack in France in 2015, a Europol internet referral unit was established to remove terrorist and extremist content from the internet. Theresa May has recently been very vocal about the need to take down such content and plainly various member states placing pressure on internet service providers will have a better effect.

An important consideration for the government will be how to protect citizens without eroding their rights and freedoms. Any treaty must be underpinned by a legal agreement because the UK will withdraw from the jurisdiction of the European Court of Justice (ECJ) on leaving the EU. This will deny British citizens the ability to challenge any aspect of a treaty at a supranational level. 

In December 2016 the ECJ ruled that “general and indiscriminate retention” of emails and electronic communications by governments was illegal. The case had been brought by David Davis while he was a backbench MP, along with Labour’s deputy leader Tom Watson, because of concerns about the legality of GCHQ’s bulk interception of call records and online messages.

The case was referred to the ECJ by the Court of Appeal to clarify EU law on surveillance. There will be no such check on the use of such powers once the UK leaves the EU.

In an increasingly insecure world, it is important that there is no gap in protection for the UK’s citizens. Unfortunately, there is a tension between sovereignty and ensuring security. It may be preferable to surrender some of the former in order to enhance the latter.

Mark Cotter Q.C. took silk in 2017, following a highly successful career as a junior specialising in serious and heavy crime (both for the prosecution and the defence).  He undertakes a significant amount of private work and has, for many years, been ranked in Chambers and Partners as a leader in the field of crime at the London Bar.

Gemma Linfield is an experienced extradition barrister and has been involved in some of the most complex and high-profile cases. She frequently appears in the High Court on matters of complexity. Gemma is ranked in Chambers and Partners 2017 as a leader in the field of extradition at the London Bar.

This article first appeared on The Times' Brief Premium website, on 26 September 2017, and is accessible online here.