In these straitened economic times, savings must be found across the whole criminal justice system. But with the dust barely settled on the advice deserts created by the government’s brutal cuts to civil legal aid, ministers are now seeking further reductions. This time the target is criminal legal aid.

It is right that those who can afford to pay legal fees should do so, leaving legal aid reserved for those most in need. Wealthy criminals should fund their costs from frozen assets. However, public confidence in our justice system is crucial, so we must guard against proposals that risk damaging its integrity.

Our lord chancellor has different priorities – demonstrating to his right-wing backbenchers his credentials as a budget-slasher, rather than his determination to uphold the rule of law. He has presented his proposals as if they are somehow consequence-free. There is no assessment of costs likely to be displaced on to other parts of the legal system, or that tendering to a smaller number of large providers will affect the nature of provision, meaning more centrally commissioned monopolies.

Nor does the loss of a localised service – the benefits of which include strong working relationships with local courts, police and the CPS – warrant any regret. And the prospect of the same companies running our prisons, prisoner transfers, probation services and legal representation – a situation that would be a serious conflict of interest, and must be avoided– is likewise ignored.

Lawyers are trained to look for evidence to support their case, yet there is little to support government claims of ‘savings’. The consultation document is an embarrassment, lacking a breakdown of how ‘savings’ are calculated. In fact, it has taken parliamentary questions that I tabled for ministers to admit that ‘in order to ensure the price competition delivers a saving to the legal aid fund, we are proposing to set up a price cap at 17.5% below the rates paid in 2012/13… which is expected to ensure savings of £118m per annum’.

So most of the savings come by simply slicing 17.5% from the budget. It remains to be seen whether the fees cut will make it all but impossible for most local providers to remain viable, an outcome which would be used by the government as a vindication of purchasing in bulk from larger providers.

The justice secretary routinely characterises criminal legal aid solicitors and junior criminal barristers as ‘fat-cat’ lawyers. One might argue such behaviour is not befitting of a lord chancellor, but Chris Grayling grasps that the legal profession has an image problem and means to exploit it in the media.

Removing an individual’s liberty is one of the most important powers in the gift of the state. Properly administered legal aid means all individuals charged with a criminal offence are represented and ensures our country’s precious rule of law applies to everybody. Legal aid helps those wrongly accused maintain their innocence and ensures the state proves beyond a reasonable doubt the case against a defendant. Many miscarriages of justice in this country happened because of an absence of proper representation, and legal aid also ensures victims have confidence the genuine perpetrators of crimes are prosecuted and punished.

No one wants a second-rate system where you are forced to accept whatever representation you are given regardless of quality. Grayling’s proposals will see the quantity of proceedings as the primary driver. Ignoring the quality of representation is a mistake as it may lead to increased pressure to plead guilty – regardless of whether the individual committed the crime – creating a system of state-sponsored miscarriages of justice.

The legal system cannot be insulated from pressure on the public purse. But I do not want a legal system with its integrity undermined. Instead, we need an urgent strategic review looking at the system in its entirety – from charge to prosecution to verdict – to examine whether our current system is fit for future challenges, rooting out inefficiency and bureaucracy. Confidence in the justice system is precarious at the best of times. It is far too precious to allow it to be undermined by ill-thought through, dogmatic proposals.

Rt Hon Sadiq Khan MP is shadow lord chancellor and justice secretary