LISBON (Reuters) - London’s popularity among Europe’s tech startup hubs has slumped as Brexit approaches and the city only kept its top spot in an European industry survey published on Tuesday by a narrow margin.

Canary Wharf skyline and the City of London can be seen from the Sea Containers building in London, Britain, October 11, 2018. REUTERS/Henry Nicholls

The survey of 540 tech founders showed that London’s popularity dropped to 41 percent in 2018 in a weighted vote, down from 55 percent in 2017. Berlin followed with 40 percent, according to the survey by the European Startup Initiative, a nonprofit organization.

London’s popularity is partly because it attracts more investment money for startups than anywhere else. It captured 53 percent of all startup investment in the European Union last year, the survey said.

But after Brexit it might become more difficult or less attractive for tech startups to base themselves in London.

“With Brexit looming the question is pressing, how the still fragile network of European startup hubs will react when an important bloodline is pinched off,” the organization said in a statement.

The second tier of European startup hubs was unchanged from the previous year with Barcelona and Paris remaining in third and fourth position with around 20 percent of the vote each.

The biggest gainer was Lisbon, which jumped into fifth place from eighth with 12 percent of the vote, ahead of Amsterdam, which dropped into sixth place from fifth. Lisbon has gained ground thanks to the city hosting Europe’s largest tech event, the Web Summit.

The survey found the top five cities received about 50 percent of all founders’ votes.

Dublin and Stockholm fell out of the top 10, replaced by Munich and Milan. Zurich jumped into ninth position thanks to its popularity among fintech specialists, followed by Copenhagen.

The survey’s main question to tech company founders was: “Where would you start if you could begin all over again?”