These Regulations are made under sections 19 and 20 of the Prosecution of Offences Act 1985 and they—(a) enable magistrates' courts, the Crown Court and the Court of Appeal to make orders as to the payment of costs which have been unnecessarily or improperly incurred in criminal proceedings (regulation 3);(b) provide for the determination and review of costs payable out of central funds (regulations 4 to 13);(c) apply sections 16, 17 and 18 of the Act to certain categories of proceedings in magistrates' courts and the Crown Court to which those sections would not otherwise apply (regulation 14);(d) make provision for the payment out of central funds of expenses incurred by witnesses, interpreters and medical practitioners (regulations 15 to 25), and(e) enable the Lord Chancellor to recover sums paid out of the legal aid fund or central funds where a costs order has been made in favour of a person in receipt of legal aid or in whose favour an order for the payment of costs out of central funds has been made (regulations 26 and 27).