Prison numbers could end up being further inflated once MPs debate revised sentencing and cuts to legal aid, campaigners have warned.
Last week's U-turn on sentencing discounts appears to be just the first chapter in the passage of the controversial legal aid, sentencing and punishment of offenders bill through parliament.
Writing for politics.co.uk, Prison Reform Trust director Juliet Lyon suggested the bill risked missing an opportunity to address England and Wales' "distorted" prison system.
"The big risk is in bashing an already beleaguered prison service for failing to cut crime whilst expecting it to do even more with even less," she argued.
"Improving prison performance represents an important but partial solution to a pressing economic and social problem. The bill stands or falls on whether the measures it contains succeed in limiting prison numbers to an unavoidable minimum."
The opposition is set to object to plans to limit the number of prisoners remanded in custody, which it claims is just a cost-cutting measure.
The number of indeterminate sentences is also set to be cut and replaced with more life sentences which run for a specific, set period.
"Labour's position is clear – offenders must be rehabilitated and not pose a risk to the public and proper due process must be followed before their release," shadow justice secretary Sadiq Khan said.
"We will not accept plans that water-down the protection given to the public by indeterminate sentences for public protection."
Cuts to social welfare legal aid for the poorest and most in need of legal advice are also set to generate controversy.
Over 90% of respondents to the government's consultation on the planned cuts disagreed with the proposals.
"Everyone should also be able to retain confidence in their legal system and be certain that they will not be disadvantaged because of the amount of money they are able to contribute towards legal costs," Plaid Cymru's Westminster leader Elfyn Llwyd said.
"The cuts not only undermine the reforms the government is promoting – if implemented, they would undermine the very principles on which the justice system rests."