In Brexit, London startups see risk — and some opportunities

There is a lot of uncertainty from a regulatory point of view, said CEO Frank Bertele, a German national.

Since the vote, he has accelerated plans to expand into the U.S.

London's tech companies will scramble to cope — though true to the startup community's culture of adaptability, many are looking to the tumult also as a source of opportunity for new business and to gain ground on the less nimble established companies.

According to Pat Saini, the head of the immigration team at law firm Pennington Manches, it costs upward of 5,000 pounds ($6,650) in visa costs and related fees to hire a person from the U.S. or another country outside the EU.

DueDil landed three contracts in two days from investment-keen American equity firms that wanted to profit from the drop in the British pound and access DueDil's database of detailed information about private firms in the U.K.

Neil Rimer, co-founder of venture capital firm Index Ventures, says that's unlikely in the longer run as it will be in the interest of the British government, whatever the future trade relations with EU countries, to keep attracting talent and encourage startups.