Police are trying to track down more than 4,000 suspects who have jumped bail in London in the last two years.
They include more than 500 alleged serious offenders who have absconded after being bailed by either the police or the courts.
The figures were obtained by campaign group The Taxpayers' Alliance under the Freedom of Information Act.
The Metropolitan Police said it had made "significant improvements" in arresting bail evaders.
The Taxpayers' Alliance, which campaigns for lower taxes, said the figures reflected "very badly" on the Metropolitan Police.
Of the 4,037 wanted suspects, 518 are wanted in connection with offences including assault, robbery, burglaries and rape.
Blair Gibbs, of the Taxpayers' Alliance, said they requested the figures to see if the Metropolitan Police gave value for money.
"If the police, who we all fund through our taxes, cannot catch suspects who skip bail, private bail bond companies should be brought in to do the job," he said.
The police can detain a suspect in custody or release them on bail prior to their first appearance at court.
Once the case reaches court, bail issues are then decided by the bench.
A Metropolitan Police spokeswoman said the force had reduced its backlog of outstanding bail-related warrants by 60% since August 2004.
"There have been significant improvements in warrant management during the past two years," she said.
Major strides
Shadow home secretary David Davis said it was the government's responsibility to ensure there was enough capacity to hold "dangerous suspects".
"This is yet another consequence of Labour's failure to address the chronic lack of capacity on our prison estate," he said.
The Home Office said that, nationally, the number of outstanding bail-related arrest warrants has been reduced by 48% since August 2004.
"We have made major strides in improving how we deal with those who breach bail," said a spokesman.
"The government has made it clear that there will be prison places for those serious, sexual, violent and prolific offenders who ought to be in prison."