With Britain's exit from the EU last week, some high-profile tech companies are now threatening to pull out of the UK, international employees are questioning their immigration status, and new VC funding appears to be uncertain.  More than one-third of Q1 venture capital investment in Europe was made in London, where startups have benefitted from the free flow of European labor and an unobstructed path to EU-wide regulatory approvals.  Some startups such as Berlin-based Number26 are reconsidering entry into the UK market.