Prisoners are spending too much time stuck in their cells watching daytime television because of a lack of resources, the Chief Inspector of Prisons has said.
Inmates were locked up and workshops were empty because there were not even enough resources to get prisoners from their cells to the activities, Nick Hardwick said.
And in some jails up to one in 10 prisoners were now saying abuse of prescription drugs handed out officially by staff was an issue for them, he said.
On one visit to Britain's largest jail, Wandsworth prison in south west London, excellent workshop facilities "stood almost empty and too many staff appeared indifferent about the prisoners in their care", he said.
Describing the situation as "shocking" and "frustrating", Mr Hardwick said prison managers would say resources to get inmates from the cell to the workshop were not there.
Cuts meant there were now fewer officers to supervise prisoners and fewer managers to supervise officers, he said.
"It would be better if prisoners were out at work and some activity, rather than lying on their backs in their cells watching daytime telly," Mr Hardwick said.
"But on the whole, the reason why they're in their cells in the daytime is either because the activity isn't available or because no-one's making arrangements to get them from the cell to where the activity is.
"If that's the case, then I don't think it's that people are making a positive choice that they'd rather watch daytime TV than go to an activity.
"It's that they're stuck in their cell and they've got that and that's there."
He went on: "In a sense I think TVs in cells are a compensation sometimes for a lack of activity and it would be better if there were more constructive things for them to do."
Too many governors and prison managers were now stuck behind desks juggling budgets rather than out on the wings setting good examples for their staff, he added.
"What tends to happen is that governors and senior managers are spending too much time in their office behind computers looking after budgets and not enough time on the wings leading by example," he said.
But he praised the management of Manchester prison, formerly known as Strangeways, where the governor was doing rounds, workshops were "busy and purposeful and wing staff knew exactly who was not at work and why".
Launching his annual report for 2011/12, Mr Hardwick said the "strains on the prison system were beginning to show" and before any further cuts, ministers need to consider that the "pressure is telling".
He also warned that problems with the abuse of prescription drugs, in particular painkillers, were spreading to mainstream prisons and was now a "major concern".
"In too many prisons now, the staff bring them out and they hand them out to prisoners in an orderly queue, or not so orderly, where they then subsequently get abused," he said.
"I think that is a spreading problem and we've seen it spread from the high security estate into the prison estate generally.
"It's very rare now that I go to a prison where that's not a significant issue."
Mandatory drug testing should be extended where possible and the GP service, pharmacies and the prison service need to work closely together to ensure inmates were getting the right treatment and prescriptions, he said.
Prescribed drugs "quite often" get stolen or bullied from vulnerable prisoners, or even sold on, he said.
"What you then end up with is people taking drugs they're not intended for, potentially mixing them with other sorts of substance which is a very dangerous cocktail.
"We see that now in pretty much every prison that we go to.
"I don't think the Prison Service is sufficiently cited on the issue."