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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Nicola Sturgeon will today pledge that her party will work with others to bring about "positive change" for ordinary people across the UK.
Half of teachers said the number of youngsters dealing with difficulties, such as depression, has risen compared to two years ago.
David Cameron will use a speech today to set out plans for patients to be able to access hospital services seven days a week.