Consumer desire for apps is certainly there, but I fear an emerging 'app gap' between demand and supply. With the current dearth of STEM (science, technology, engineering, maths) skills - the EU predicts 900,000 IT-related job vacancies by next year - how will we meet the potential of the app economy, if we don't have the skills available to write those apps?
There is a lot that London and the UK can offer. London in particular is the mothership of global finance. The media industry is based here along with government and great universities and business schools. Also, English is the native language of the technology industry, so the UK has the advantage over other countries.