The council tax protester Sylvia Hardy is to be released from jail on Friday - three days earlier than the original seven-day sentence.
Sylvia Hardy arrived at court with a packed bag for her jail term
Ms Hardy, 73, from Exeter, Devon, was sent to Gloucestershire's Eastwood Park Prison on Monday after missing a deadline to settle arrears of £53.71.
She had refused to pay part of an increase in her council tax.
Supporters of the pensioner have been holding a vigil for her in the grounds of Exeter Cathedral.
Organisers of the vigil said they would be at the cathedral between 1000 and 1600 BST for the rest of the week.
Only two protesters will be at the cathedral at any one time, but organisers said it was enough to keep Sylvia Hardy and the council tax in everyone's thoughts.
Stan Fitton, one of the organisers, said: "Judging from the passers-by, most people are fully aware of what's happened to her and we've had a lot of sympathy and interest."
Ms Hardy, a retired social worker, became the first woman pensioner to be jailed in England for refusing to pay more than the rate of inflation on a council tax increase.
Magistrates on Monday said they had no choice, but to send her to jail adding she should not be seen as "a martyr".
Ms Hardy told the court that she was fighting to change a law which she saw as unjust, and "often the only way to do this is to break the law or ignore it and to accept the punishment".
Local Government Minister Phil Woolas told the BBC that he did not agree with Ms Hardy's stance.
He said: "I don't see how she can refuse to pay it for political or principled reasons as she sees it.
"If people don't like something, then of course they can protest, that's always been the case in Britain.
"But if people can afford a tax, and I believe that in this case she can, then it's not fair on other council tax payers if they do not pay."
But Britain's biggest pensioner organisation, the National Pensioners' Convention, condemned the sentence.
Sylvia Hardy's supporters are protesting at Exeter Cathedral
Convention president Frank Cooper said: "Sylvia has taken a courageous stand to highlight the inadequacy of the basic state pension by showing how difficult it is for millions of older people to make ends meet and pay their bills."
Ms Hardy was said to be in a "good frame of mind" after her first night in prison, council tax activist Albert Venison said, although she did not sleep well because the cell's hard bed aggravated a back condition she has.
Mr Venison added that he learned she would be freed from prison on Friday morning because the jail did not release prisoners at the weekend.