A period of 18 months saw almost 46,000 NHS prescriptions containing patient details go missing either through loss or theft, the government has revealed.
Responding to a request from the Tories, health minister Dawn Primarolo said there were 241 separate incidents where batches of the forms were lost or stolen between April 2007 and November 2008.
The forms went missing in transit between pharmacies in England and the arm of the NHS which reimburses costs.
It is the equivalent of 130 single prescription forms going missing per day – a rise of 49% on the previous year, when almost 31,000 were lost or stolen.
Information contained on the forms include a patient's name, address, NHS number, date of birth and details of the drugs they are prescribed. Some also include a National Insurance number if the person is exempt from payment.
Shadow health secretary Andrew Lansley said: "This isn't just the odd mistake here and there; this is now equivalent to almost 200 prescription forms lost every single day."
But the government defended its record, saying that more than 99.9% of prescriptions are processed securely.