Under-pressure probation officers are braced for more strain after the autumn when Ministers will announce proposals to slash budgets and impose fewer short-term prison sentences.
It will mean probation trusts missing out on vital funding at a time when they will be asked to supervise rising numbers of offenders in the community.
Specialist programmes aimed at stopping reoffending have already been scrapped, and experts have warned that crime will soar as petty criminals are monitored less closely.
Some fear that criminals who are deemed to be at low risk of reoffending could slip under the radar and go on to commit serious offences.
Mark Siddall, operations director of West Yorkshire Probation Trust, which has seen its caseload rise by seven per cent in a year, said it would be impossible to achieve the Government's planned budget reductions without cutting services.
"I am clear that we will end up stopping some of the things we do now and there is no point in trying to be dishonest about that.
"We will maintain our current approach to the most dangerous and most prolific offenders, that is sure.
"But the problem for local communities is that the majority of people who commit serious offences are either people who are not in the criminal justice system and suddenly commit a rape or murder, or if they are in the criminal justice system they are people not being managed because of a sexual or violent offence.
"They tend to come from the lower tier of offenders, and if we have a light touch on lower-tier offenders there is the potential risk that we might get more of those cases.
"We cannot continue to have a seven per cent increase in our workload each year without additional funding."
Justice Secretary Ken Clarke announced plans in June for a "rehabilitation revolution" which would see more criminals given community orders to tackle the prison overcrowding crisis.
The idea is supported by probation officers, who say community orders are more effective than prison in reducing reoffending, but its success will depend on how deep the funding cuts will be.
Roz Brown, chief executive of South Yorkshire Probation Trust, which has already trimmed its budget by up to 800,000 this year, said managers would be "working somewhat in the dark" until the autumn.
"We are not a protected part of the public sector so we are looking at 25 per cent cuts at least, maybe up to 40 per cent," she added.
"If they cut our budget by 40 per cent over the next three years we will obviously have to do the best we can, but of course there will be an impact."
The region's probation trusts have already begun work to reduce costs by exploring whether they can pool resources in "back-office" departments like human resources and finance.
A programme aimed at tackling binge drinking in South Yorkshire has been scrapped, management structures have been scaled back, and bosses have decided not to fill staff vacancies in all but critical positions.
Peter Brown, chief executive of York and North Yorkshire Probation Trust, said another option could be to adopt a scheme being trialled in Bradford, in which criminal justice agencies liaise with each other to ensure that services are not duplicated.
"We are not in the position where we have to make redundancies," he said. "We are not there yet."