"Europe stands by UK in fight against terrorism" tweeted EU Council President Donald Tusk after London was hit by a terror attack Saturday. Britain was also shocked by attacks in March and May.
Cooperation between Europe and Britain on security matters, however, might soon change due to Brexit, Britain's decision to leave the European Union following a referendum last year.
Saturday's incident killed seven people and left almost 50 wounded. Islamic State claimed the attackers were part of its terror network and several people were arrested and named.
Andrew Duff is a former liberal Member of the European Parliament and visiting fellow at the European Policy Center. He believes the recent attacks will mean a higher profile for the security aspects during the Brexit talks.
"It should be possible for the UK to negotiate its continuing use of the SIS 2 [Schengen information system] data exchange platform and to continue to be a member of Europol [the EU's law enforcement agency].," he said. "But participation will be at a financial cost and strong institutional connections will have to be invented, including recognition of the ultimate judicial authority of the European Court of Justice."
New face of cooperation
In recent weeks, experts and leading security specialists in Britain have warned about the importance of cooperation on intelligence and security if Britain wants to fight terrorism.
Technically speaking, security issues are not part of the Brexit negotiations, as the European Union wants to first settle issues on citizens' rights and financial matters before speaking about future cooperation between the bloc and Britain.
British Prime Minister Theresa May was tough in her letter late March that triggered Article 50, the official notification to leave the European Union.
She wrote: "In security terms a failure to reach agreement would mean our cooperation in the fight against crime and terrorism would be weakened."
May has publicly stated that "no deal is better than a bad deal," but recent events might question that logic.
Rosa Balfour, a senior fellow at the German Marshall Foundation, said when it comes to security, a hard Brexit will affect Britain more than the EU.
"The UK would be more isolated and its ability to deal with security issues, which requires cooperation, would be reduced ... where EU member states would continue to cooperate amongst each other," she said. "... If you're outside [the EU], you don't have the institutions and you don't necessarily have the trust if the [Brexit] negotiations don't go well."
How much influence the recent attacks have on Britain's politics will become clear Thursday when national elections are held. May called an election when her party was riding high in polls in the hopes of getting a clear mandate from the public before Brexit negotiations start June 19.
The advantage of her Conservative Party has fallen. Most likely they will even be short of a majority, which will further complicate the exit negotiations.
Claude Moraes is a British Member of the European Parliament for the Labor Party and chairs the parliament committee on civil liberties, justice and home affairs. He said security will be one of the issues during the coming negotiations, but not the main one.
"The prime minister made a very political statement after the attacks where she talked about a more proactive response, but many of those were about international agreements," he said. "Like, the internet taking down material which would radicalize potential subjects, and also issues about how terrorists communicate on the internet."
Moraes urged a close working relationship with the EU, as he believes terrorism can only be countered with an international approach.
One of the approaches Britain could explore on security matters is the deal that Denmark struck with the EU. After a referendum, a majority of the Danish population refused to follow EU justice and home affairs policies. Despite the outcome of the referendum, Denmark will still be allowed indirect access to data and officers will still be posted at Europol headquarters.
Other security matters are moving along in the European Union without Brexit. The EU Commission will share its plans and vision for a common defense fund on Wednesday, a move long pushed back by Britain.