>"and where seeking consent was not practicable," //
As they have your contact details and next of kin details then seeking consent must be quite practicable.
I expect them mean "commercially financially viable". Those people the NHS can't simply look up a phone number for (from doctor's surgery records) and ask (or ask their guardian/parent) must be in the few hundreds [of those they have sufficient medical information for to be used in a scientific study].
I guess that's what it says, practicable with regard to cost.
To look at one random example, the first study on the list of approvals in 2013 was the "ETPOS: European Transfusion Practice and Outcome Survey". Apparently they took data from 10,000 patients who had blood transfusions and tried to see if there was any correlations between practices such as "ratio of red blood cells to other blood component therapy, such as plasma and platelets" and health outcomes. I guess it was deemed that phoning each of the patients was impractical.
Robot Dialer: The NHS wish to sell your medical data for use in a study of people who had blood transfusions. Press 1 to accept, 2 to refuse, 3 to speak to an agent.
Robot Dialer: You pressed 1 to accept; can we use your data for future studies? Press 1 to accept, 2 to refuse, 3 to speak to an agent.
Robot Dialer: You pressed 2, can we contact you to ask about using your data in specific studies in the future? Press 1 to accept, 2 to refuse, 3 to speak to an agent.
Umpteen marketing companies appear to be able to afford to do this sort of calling (yes even though it's against the law for them to contact me as I'm on the no-call database [which wouldn't apply to the NHS]).
If it's too costly then the studies can hardly be worthwhile? Remember the NHS wasted £10 Billion on a single IT project over the last 10 years. What would this auto-dialer have cost? £10k in "management", couple of thousand in IT staff and set-up (join study NHS numbers with main database ID table and contact info tables, select phone numbers; set-up dialer script, test, initiate) maybe £500 in direct call costs. They most likely already have systems in place to do auto-dialed calls for disease outbreaks [UK Environment Agency use one for flood warnings].
As they have your contact details and next of kin details then seeking consent must be quite practicable.
I expect them mean "commercially financially viable". Those people the NHS can't simply look up a phone number for (from doctor's surgery records) and ask (or ask their guardian/parent) must be in the few hundreds [of those they have sufficient medical information for to be used in a scientific study].