This degree of control is sufficient for the ONS to reclassify the two as public corporations with retrospective effect from those historical dates: you can read their 19-page judgment here. (This reclassification has nothing to do with Metronet going into administration, incidentally.)
Then comes the pay-off. “The inclusion of Metronet and Tube Lines in the public sector leads to changes to the key public sector finance statistics: public sector current budget (the Golden Rule measure), public sector net borrowing, and public sector net debt (the Sustainable Investment Rule measure).” The ONS considers the net impact will be "relatively small".
The real point, however, must surely be that they were kept in the dark, and only stumbled upon these Special Shares, four years after the fact, during their own researches.
What else has the Kirkcaldy Coward kept from them ?
Footnote: apparently the Government guarantee for Northern Rock will not be appearing on the national balance-sheet because it is merely a contingent liability. So – just ‘notes to the accounts’, eh ? Ask Enron shareholders about that approach …