More than half of all criminals ordered to wear an electronic tag break the terms of their curfew, a review has found.
Some 59% of offenders ordered to be tagged by courts receive at least a warning, while more than a third are sent back to court following more serious violations, according to an analysis of more than 80 cases by Her Majesty's Inspectorate of Probation (HMIP).
But Chief Inspector Liz Calderbank said the most concerning finding was that in a fifth of cases where there were violations, inspectors could not even see who was supposed to be in charge.
Justice Secretary Kenneth Clarke set out proposals to extend the use of tagging in plans to radically overhaul community sentences in March. Their use by courts has already more than doubled in the last six years, with a total of 80,000 offenders being tagged in 2010/11.
This included 65,000 by courts and 15,000 who were released early from prison, costing some £100 million, about a tenth of the total probation budget - but the system is cheaper than the £45,000 annual cost of a prison place.
Use of the tags was up from a total of 51,000 in 2005/6, including 31,000 by courts and 20,000 post-release, figures in the report showed. But the inspectors found court paperwork was unclear, illegible or wrong, leading to delays in enforcement or action having to be stopped once it emerged that the person who thought they were responsible had no legal authority.
The identify of the offender manager responsible for taking any action could not be established from the paperwork because it was often unclear whether it was a single requirement order, for which the tagging firms were responsible, or one with multiple requirements, for which the probation service were responsible.
"This is why we are so concerned about the lack of court administration," said Ms Calderbank.
Home Secretary Theresa May said the findings of the review would be examined "seriously" and changes made if problems are continuing to arise.
She told BBC Breakfast: "I recognise that there are issues that the Chief Inspector has raised that will have to be looked at seriously. We will have to look at this report to see whether there are lessons to be learned and whether there are any changes to be made. If there are problems that are continuing to arise, then that will need to be dealt with."