There is reason to believe that the courts charge is pressuring some defendants to plead guilty even in cases where they may be not guilty factually or may have a legal defence. Furthermore, a number of Magistrates have recently resigned from the bench citing the lack of justice inherent in this charge as a reason - The Times 25th July 2015 (£)
The legislation contains provision for interest on the charge if or to the extent that it remains unpaid.
Ministry of Justice Fact sheet
Law Society Gazette - Society outrage at 'back door' criminal court fees - the Law Society President described the charges as ‘outrageous’ and a threat to fair trials.
Halsbury's Law Exchange
The Justice Gap
Link added 30th August:
Transform Justice 26th August - How did the criminal court charge get through Parliament?