According to technology and investment advisory firm GP Bullhound: London is still home to Europe’s largest $1 billion tech company, but maintaining that lead post-Brexit may be more difficult.

Nowadays, London is home to 13 unicorn businesses, more than Madrid, Stockholm and Amsterdam combined. Growing technology sector fintech from the British capital is one of the main sources of big companies, with Monzo, TransferWise, and Revolut being among the city’s current crop of unicorns.

GP Bullhound data covers technology companies working in areas including artificial intelligence and machine learning, big data, cybersecurity, marketing and digital media, e-commerce, cloud computing, financial technology and healthcare technology.

It also predicts that The UK will host 25% of the $1 billion European start-up created in the coming years. Given their own figures saying that the UK now has 30% unicorns.

Sadiq Khan, Mayor of London, emphasized that the British capital remains open to business, talent and investment from around the world. As reported by his communications agent: “London is an excellent place to start, grow and develop an international business. Starting from artificial intelligence to fintech, London is home to many exciting companies that lead the way in developing world-changing innovations and ideas. We love welcoming more international companies than any other city and today’s numbers show that London is open to investment and talent from around the world.”

Manish Madhvani, GP Bullhound Co-Founder and Managing Partner added: “London is the heart of Europe’s tech worldand it’s great to see so many unicorns currently here, along with a number of contenders likely to reach the next status.” The challenge now is for London unicorns to get ahead, and most importantly for investors to support them with more resources so they can challenging Silicon Valley dominance, bringing Europe its first tech titan.”

Few would argue that the UK, and particularly London, is Europe’s leading technology hub. Will you maintain this advantage after Brexit? In the past year, technology investment in the UK has fallen significantly, while investment in the rest of Europe has increased.

Four in 10 tech companies say they are considering a move or establishing operations outside the UK as a result of Brexit.