Figures obtained from the Crown Prosecution Service show that, on average, about two cases were dropped per day last year as a result of delays in bringing them to court or because of an abuse of process.

The data show that 1,078 cases were dropped because of failures in disclosure during the first nine months of last year, up from 567 in the whole of 2014.

There is a legal obligation on police and prosecutors to disclose any material that may assist the defence.

Caroline Goodwin QC, chairwoman of the Criminal Bar Association, said: “Disclosure of unused material in criminal cases is a core justice duty.

“The government has a constitutional and moral duty to ensure that there is sufficient funding across the system to ensure a good and proper disclosure regime.

“This starts at the grass roots, from the commencement of an investigation, with sufficient and appropriately trained police officers, to source, locate and retrieve material relevant to an inquiry.”

A CPS spokeswoman said: “There has been an unprecedented effort by the CPS and police in the last two years to overhaul working practices and make sure we are getting disclosure processes right. We have been clear these significant cultural changes will not happen overnight.”