The 13 European tech startups that are most likely to be worth $1 billion next

Roughly three European tech companies a year have been sold or floated on the stock exchange, or otherwise valued by investors, at $1 billion or more since 2000, according to data from British investment bank GP Bullhound.

But since April 2014, Europe has added 13 companies to its list of "unicorns." (Three firms - London-based online fashion retailer Boohoo.com, Spanish online travel company Edreams, and British mobile money firm Monitise - dropped off.) The continent now boasts forty $1 billion dollar-plus companies.

GP Bullhound's report also sets out which tech firms we're likely to see reach billion-dollar valuations next.