Up to £230m has been spent "needlessly" holding people on remand in custody who eventually avoided jail, a penal reform charity has said.
More than 35,000 people kept on remand in 2013 went on to be either acquitted or be given non-custodial sentences, according to new figures obtained by the Howard League for Penal Reform from the Ministry of Justice through a Freedom of Information request.
Data from both crown and magistrates' courts in England and Wales suggests the total number of people held on remand in 2013 reached 72,877, while in the 12 months to June this year there have been about 11,594 people in prison on remand at any one time.
The charity condemned the figures as a misuse of the remand system but the Magistrates' Association said the charity's analysis was "misguided".
Howard League chief executive Frances Crook said: "Our prisons are squalid and our prisoners are idle, yet the courts are continuing to remand innocent people and people accused of petty crime at huge public expense.
"It is time to end this unjust system, which is costing the nation money that could be better spent."
Last year, magistrates remanded 25,413 people, about 71% of the total 36,044 held, who did not eventually get jailed. With defendants held prisoner for an average of nine weeks and a prison place costing £37,000 a year, the charity estimated it cost the taxpayer £165m.
Meanwhile, j udges sitting in crown courts remanded 36,833 people, of which 27% or 9,844 were acquitted or avoided custody upon sentencing. That cost £65m.
A charity statement added: "The figures suggest that there is widespread overuse and misuse of remand across England and Wales - despite the recent introduction of new legislation designed in part to reduce the number of people locked up needlessly.
"People on remand receive a very poor regime when in prison. Overall they spend more time locked in their cells, receive less help and support when inside, and are inadequately prepared for release. Remand prisoners are also at the greatest risk of self-harm and suicide.
"Remand is currently the key driver of the rising prison population. Its misuse puts further pressure on the country's overcrowded and under-resourced prison estate, where suicides and assaults have risen alarmingly after the number of officers was cut by 30 per cent in three years."
The Magistrates' Association said its members might have several reasons for refusing a defendant bail, including the commission of further offences, the flight risk and interfering with witnesses.
Chairman Richard Monkhouse told the BBC: "The decision to remand a person in custody is one of the toughest our members have to take. In doing so they are assessing risk and fulfilling their duty to apply the law.
"The suggestion that there is 'widespread misuse' of remand is misguided. Very careful consideration is taken by our members when doing their job in administering the law."