It's a recurrent theme in British politics. Look up Harold Wilson's 1963 "White Heat of Technology" speech and the creation of the Ministry of Technology.
Britain within living memory has been a technology leader in aviation, nuclear, computing, Those were largely developments that came out of the war and declined in the face of a dependence on government money for investment (and in the latter case, an unwillingness to admit even to the existence of the technology).
Private investors aren't interested in long-term investments - the "investment banking" industry has become big largely because it's eschewed actual growth-producing investment for complex financial instruments which are essentially a form of privatised taxation.
There is still a lot of high-tech industry (take Rolls Royce aero engines for example), but it survives and grows pretty much in spite of the business environment. It's no accident that Britain's now successful, productive and growing car industry is owned and financed from Japan, Germany and India.
It may be possible to grow IT-based industries in London, but they won't be owned in London and nor will any IP associated with them. And I'm afraid the government is sufficiently clueless about technology that it might actually feel it needs to encourage businesses like those cited by the article ( Instagram, Skype and Groupon) whereas there is probably a lot to be said for actively discouraging them.
Plus, this seems to be all about exempting businesses from paying their normal dues. I'm all in favour of foreigners spending money in London. I'm not in favour of the government giving it back with interest to encourage them.