Devolution for England?

When I see the statistics on the level of government spending as a percentage of regional income in different parts of the UK (via Vindico), I can't help thinking what a wonderful thing English independence would be, as it would enable us to reduce taxes by at least 7%*

In summary ...
Northern Ireland 70.5%
Wales 64.3%
Scotland 55.6%**
England 41.0%
United Kingdom (average) 44.1%

* 41% divided by 44.1% = 93%. The maths is trickier than that of course.

** To be fair to Scotland, the North East of England comes in higher, at 63%.