Vicky Pryce, 60, emerged from East Sutton Park Prison near Maidstone, Kent, via a back exit.
The mother-of-five was driven away with her lawyer Robert Brown, pursued by press photographers who been camped outside the Category D open jail for women and young offenders.
The ex-wife of former Cabinet minister Chris Huhne's has served around a quarter of an eight-month sentence for taking speeding points for him.
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The 650-feet long hole emerged after a water main burst near the 14th-century Ponte Vecchio bridge.
European Commission President Jean-Claude Juncker invited the former London mayor to Brussels to get a more 'accurate view of the EU'.
Heard cited irreconcilable differences as reasons for the divorce, court records show.