The Public Prosecution Service conducts all cases it prosecutes, including those on behalf of the Environment and Heritage Service, in accordance with the Test for Prosecution. That test is whether there is sufficient available evidence to afford a reasonable prospect of conviction and, if so, whether it is in the public interest to prosecute. If the evidential aspect of the test is met, there is a strong presumption that prosecution is in the public interest; the more serious the offence, or its consequences, the stronger the presumption. The cost of bringing a prosecution does not weigh in that consideration. The PPS may take into account, in assessing the public interest, whether the offence is of such a nature that it is likely that the court will impose only a very small or nominal penalty.
The cost-effectiveness of prosecutions is based on the overall efficiency of the PPS. It is not connected in any way with the fines imposed following conviction. Such fines are not payable to the PPS. Following conviction, the PPS will usually ask for its costs to be paid by the defendant but whether such an order is made, and to what extent, is a matter for judicial determination.
The cost-effectiveness of the PPS and what is being done to maintain and improve efficiency is the subject of the PPS annual report and business plan, copies of which are available in the Library of the House.