That's quite a persuasive figure and definitely adds weight to what you're saying. London also generates 22% of UK GDP, which is the biggest single contributor but even so, the spend per resident doesn't really seem equitable.
Another question to consider on public spending is proportional tax take on income tax (i.e. who fills the government pot with money). For 2013,this is the split
Northern Ireland 1.8%
England (and specifically London) are filling the UK coffers the most so should they get the most back, or is the fact that they are getting the most back the reason that they are filling the coffers the most?
If a person can answer that question definitively the first way then they'll probably vote tory; the second way and they'll probably vote labour.
To me though, this is a murky chicken and egg type question. The pragmatist in me doesn't think the UK-driven and London-centric economic structure should change until there is a viable economic alternative or the whole of the UK will be worse off... that said, perhaps there should be more investment going on outside of London to help promote that alternative..?
On the face of things it seems reasonable to suggest that London should gets more because it contributes more.
The problem with that argument is that omits two centuries of theft. Where enormous natural resources of the north were owned by landowning aristocrats who sucked the wealth out of the north and poured it into parts of the south east. Pitmen, miners, steel workers and shipbuilders in the north of England and other regions of Britain and Ireland worked for slave wages to the vast enrichment of the likes of Lord Londonderry. Just another colony of the empire.
What's worse is that these arrogant southerners often seem to think Northerners should be ever so grateful to receive a few crumbs from their overladen table. It's like bragging about winning a race to the summit of a mountain after being carried to the top on a pile of broken backs. Then kicking all the plebs who got you there over the edge and instructing them to start over again using just one leg. It's like something out of the Hunger Games.
I'm not sure what the solution is at this point. Thatcher put the nail in the coffin of the North 30 odd years ago and not much has changed. The North is going to have to regenerate itself, but the natural resources are mostly gone now. And if anyone thinks that shale gas, being extracted from this 'desolate region of the country', will bring some wealth to the region, then they must look at the lessons of history. The south will get the money and the north will have to pick up the pieces.
I know Paris was/is similarly dominant in France. I believe they built a high speed rail network in an attempt to shift capital between regions. I'm not sure how successful that was. We're getting something similar here (HS2) but many suspect it will just further exacerbate the problems. Maybe federalisation of larger regions, but then would Liverpool, Manchester and Leeds corporate and work together? Probably not.