The shift towards more summary justice is driven by financial concerns and will not improve public confidence in the criminal justice system, magistrates have warned.
In a letter to the prime minister, the Magistrates Association says that although JPs want to dispense speedy justice, the extended use on-the-spot fines on the grounds of cost-effectiveness "cannot be right".
"There is a growing belief that the extended use of fixed penalty notices and penalty notices for disorder is considered only as a financial rather than a judicial solution to crime and does not result in a better society and increased public confidence," it says.
The concerns are raised in a new report from the association warning that a lack of funding in the courts system is delaying and stopping criminals being brought to justice.
It notes that 150 courthouses have been closed in the past decade, causing those involved to travel further and even resulting in some cases being cancelled, and says a lack of clerks and legal advisors is causing further delays to the system.
"All of us wish to get cases through the courts as fast as possible, but it is very frustrating when there are delays caused by lack of money," association chairwoman Cindy Barnett told Today.
Shadow home secretary David Davis said the findings were "astonishing", adding: "Cut price gimmicks and initiatives at the expense of properly implemented justice in court betrays the victims of crime and allows too many criminals to get off lightly."
Lord Falconer, the lord chancellor, acknowledged there were "considerable constraints on public expenditure" but said efficiency savings meant there should be no cuts to services.
The magistrates claim they are facing a 3.5 per cent annual cut in real terms funding in the coming years, but Lord Falconer insisted that over the last decade, investment in the criminal justice system had gone up from two per cent of GDP to 2.5 per cent.
"The issue is not a lack of resources - but there are problems because money is not unlimited - it is making sure all of the people in the system work effectively together," he explained to Today.
"The courts can't do their job if the papers aren't there, the courts can't do their job if a summons is not sent out, and that's why we need people working together much, much more effectively."
Today's report details how many court buildings are "severely dilapidated" and several are infested by rats. IT systems are also described as "out of date", as they are yet to link up with similar computer systems for the police and county and crown courts.
The letter to Tony Blair concludes: "We are ready to dispense simple, speedy, summary justice; we support all moves to increase the movement of cases through our courts provided that justice itself is not impaired.
"However, the extent of the financial cuts that have been made in recent years makes it impossible for the system to perform adequately. Recent proposals, putting money before the interests of justice, will only serve to diminish public confidence."