It does stand up to some scrutiny. The issue is less that companies will move away - although some might, financial institutions are notoriously nomadic (assuming any increase is modest it might not have much impact, but equally it's not likely to generate any extra revenue either). It's more about encouraging new investment. When Facebook, Apple and Google expanded UK operations recently the favourable rates of CT were mentioned a number of times. Would you rather they have gone somewhere else?
We all want a fair society. As a parent it's impossible not to be moved by child poverty. The question is how do we build the society we all want. Higher taxation (on business and individuals), more regulation, increased borrowing - I'm not sure this is the way to do it. That's not to say there is much that could be done that isn't being done, totally accept that. Labour won't achieve the society you crave with their current agenda. When they had a top rate of tax of 83% in the late 70s (98% on unearned income), did we have a Socialist utopia? The country was on its knees and the rich were paying far less as a proportion of total tax revenues than they are now. I know that Corbyn isn't proposing anything like this, but the idea that higher taxes on the rich equals more revenue and a fairer society doesn't stack up - but it might make some people feel better I suppose.
So you're concerned about financial institutions moving but voted Brexit even though several have stated in the event of Brexit they will leave Britain which it appears some are going to.
And shouldn't we levy penalties against Facebook, Apple and Google if they don't pay the taxes we demand, isn't that what Brexiteers are saying we should do to the big German car manufacturers if we don't get the deal we want?
How do we get a fairer society, well I would suggest that instead of the majority of the wealth been held onto by a very small percentage of the population that more money finds it's way back into the public pot for vital services.
Of course the top rate tax of 83% that you hi-light would be unworkable, but there's enough money sloshing around this country to improve health, education and public transport. We shouldn't be making teachers and teaching assistants redundant or cutting vital health services.
And the knock on affect is a better educated, healthier more mobile work force which leads to better productivity. It just needs a change of attitude, both from big corporations and individuals who want to grab the biggest slice of the pie they can and fuck everybody else. As I said, I would quite happily pay more tax myself.
It's nothing to do with socialism or capitalism, it's just about making the country a better place to live