London entrepreneurs have a constructive debate over the relative methods of taking venture capital versus bootstrapping your business. The city's tech scene is at a pivotal moment, continuing to boom even as the country debate's its future in the European Union, a decision which will have huge implications for the future health of the industry. Meanwhile, radical new formats and mediums are starting to be explored in earnest, from artificial intelligence to virtual reality. At Google's annual I/O Extended event in London, Business Insider sat down with a handful of exciting London Android developers and CEOs, from luxury smartphone business Vertu to fast-growing language learning app startup Memrise. We wanted to hear what they're excited -- and worried -- about over the year ahead.