It is “inevitable” some of the hundreds of inmates set to be freed from jail early will commit more crimes and end up back behind bars, the prisons watchdog warned.

Around 1,700 prisoners are expected to be released on Tuesday from jails across England and Wales in a bid to cut overcrowding. This is in addition to the around 1,000 prisoners normally freed each week.

It comes after Justice Secretary Shabana Mahmood announced plans in July to temporarily cut the proportion of sentences which inmates must serve behind bars from 50% to 40% as the Ministry of Justice (MoJ) said overcrowding had pushed jails to the “point of collapse”.

Asked by reporters if the plan will work, chief inspector of prisons Charlie Taylor said: “Let’s hope that it works as well as it possibly can.

“It’s inevitable that some of these prisoners will get recalled to custody and it’s inevitable that some of them will go out homeless. I think what’s important is that, and this is where the risk comes in, that we have, to some extent, to hope that these prisoners will go out, will settle down, and the vast majority of them will.”

Large numbers of prisoners being freed on the same day, and when the “preparation period, with the best will in the world, has been squeezed into a shorter time than you would normally expect”, “inevitably increases the risk of further offences (being committed) in the future”, Mr Taylor warned.

The “acute” numbers of people being released adds to the “possibility of risk”, he said, adding: “Although the Government has absolutely done the right thing in doing this, they really had no choice, if people are coming out, they’re not properly prepared, and they’re homeless, then what we’ll see is the danger that they’ll commit more offences, or that they breach their bail conditions, in which case they’ll end up back inside again.”

Speaking as he set out the findings of his annual report on the state of prisons in which he detailed the “desperate” crisis and his “alarm” at the prevalence of violence and drug use behind bars, Mr Taylor said the Government “had no choice but to do something about this” but had to make the decisions in “far from ideal circumstances”, adding: “The bath was in danger of overflowing, and they either had to turn the taps off or they had to let some water out.”

The watchdog has repeatedly raised concerns about shortcomings in the way prisoners are prepared for release, amid widespread problems across the criminal justice system with funding and staffing among other issues.

Asked how unprepared prisons and probation are for the move, he said: “This is an area of activity that we have been consistently concerned about.

“We know that accommodation is often very poor. We know that some of the risk planning hasn’t always been done in advance. We know that it takes time with probation services to work out things like the terms of people’s licences.”

Preparations for the early release scheme have taken place during the summer when lots of people are on holiday and despite staff having “worked their socks off” in “very difficult circumstances” to put plans in place, he added: “This is now the crunch point where people are actually leaving prison.”

He told how probation teams had expressed concerns that they face a “very big pressure” in having enough experienced staff, who are already managing high caseloads, to cope with the influx.

“There’s no getting away from the fact that despite all the good work people have done, this is certainly going to be a risky time for people coming out from prison.”

Mr Taylor also said it would concern him “enormously” to learn victims were not prepared in the wake of their perpetrators being freed early after Victims’ Commissioner of England and Wales Baroness Newlove branded it “regrettable” that some had still not been told this was happening on the eve of the policy coming into force.

“The last thing we want is people to be to be re-traumatised,” Mr Taylor said, adding: “We want prisoners to go out into stable accommodation, because that means they’re more likely to settle, they’re more likely to get a job, get on with their lives, and not create more mayhem, more victims of crime. But certainly, if that preparation isn’t done properly, then that’s a source of concern.”

Hundreds more prisoners are due to be freed early next month in the second stage of the scheme.

Mr Taylor said eight weeks was a very tight turnaround time for the policy to be put in place, adding: “We would expect preparation for release to happen more in a more timely fashion than we’ve seen this time around.”

Finding a longer term solution to the overcrowding crisis is the “challenge that this Government faces”, Mr Taylor said, adding: “There is work to be done and some decisions that the Government will need to make over future months and years in order that we don’t end up with another prison population crisis in future.”

The watchdog also suggested ministers will not be able to build enough prisons to fit all criminals set to be jailed in future unless they overhaul sentencing rules.

His report said: “With the number of prisoners projected to grow by as much as 27,000 by 2028, it is unlikely to be possible to build enough new accommodation.

“Most jails already fail to give prisoners enough to do and population increases are likely to make things worse.

“If prisoners leave prison without having learnt the skills and habits that will help them to hold down a job, if they are not being taught to read, if they are being sold drugs without support to break their addiction and if they continue to live in environments in which violence is commonplace, prisons will fail in their duty to prevent future reoffending.

“Alongside decisive short-term action, there is a pressing need for a much bigger conversation about who we are sending to prison, for how long and what we want prisoners to do while they are inside.”

Ms Mahmood said the report “lays bare the stark reality in our prisons, and the dire situation we inherited”.

“This Government will tackle the crisis head on and today, changes will come into force to prevent a total collapse of our criminal justice system that would leave the public less safe.

“If we had not acted when we came into office, there was a real risk that the courts would have been forced to delay sending offenders to jail and police left unable to arrest dangerous criminals.

“This is a temporary measure, giving us time to set about long-term change in the prison system – building the prisons we need and driving down reoffending.”