Drug companies face accusations of secretly colluding with pharmacists to overcharge the NHS millions of pounds, following an undercover investigation by The Telegraph. Pharmaceutical firms appear to have rigged the market in so-called specials" - prescription drugs that are largely not covered by national NHS price regulations. The prices of more than 20,000 drugs could have been artificially inflated, with backhanders paid to chemists who agreed to sell them. Representatives of some companies agreed to invoice chemists for drugs at up to double their actual cost. Chemists would then send inflated invoices to the NHS, allowing them to pocket the difference. Tens of thousands of the "special" drugs are not on the nationally controlled NHS price list and so costs can be manipulated by drug companies. Sales representatives for drug firms were secretly recorded by this newspaper offering to provide apparently falsified invoices allowing chemists to bill the NHS for sums far greater than they would spend. Another firm offered to pay an annual fee to chemists who agreed to offer its prescription drugs. Hundreds of millions of pounds of taxpayers money are feared to have been wasted in recent years due to the practice. The undercover investigation was launched after this newspaper was approached by a whistle-blower who alleged widespread malpractice. Undercover reporters posed as investors hoping to set up a chain of chemists.