MOF points out in his blog, that it is impossible to prepare an accurate picture of the cost of Welsh independence because there is no published data on Welsh tax revenue.
A shop in Rhyl collects its VAT from Welsh spending, but this appears in the accounts of the Companies head office in Chester.
A factory in Treorchy collects its NI contributions from its Welsh workforce, but declares it in its company accounts in Birmingham.
The profits from a multinational car components firm, with its manufacturing base in Wales, are declared as that of its UK subsidiary from its London headquarters.
It would be a simple matter to declare the source of this income on a geographical basis - it would only take a few lines in company spreadsheets and a few lines of code in government databases.
I can not believe that at some stage the UK government has not carried out this excercise - just in case we got our way - and I am certain that if the figures demonstrated that an independent Wales would be quickly bankrupt then these figures would have already been published. If as I suspect the figures showed that an independent Wales would be more than capable of being self-sufficient then the figures would be locked away to gather dust in some dusty filing cabinet.
The truth is out there ..... probably kept in the LL files!