The Ministry of Defence has been strongly criticised by MPs over the way it issued a controversial anti-malarial drug to troops on overseas operations, despite concerns over severe side effects.
The Commons Defence Committee said there was "strong anecdotal evidence" that stringent conditions laid down by the manufacturers for issuing Lariam had been ignored by the armed forces.
It called for the drug - which has been associated in a minority of users with an increased risk of psychosis and anxiety reactions - to be designated a "drug of last resort" only to be issued when there was no alternative available.
While Lariam is not the main anti-malarial drug used by the armed forces, at least 17,368 personnel were prescribed it at least once between the start of April 2007 and the end of March 2015, according to official MoD figures.
The committee said it had received strong anecdotal evidence that a body of current and former service personnel had been adversely affected by its use and that the arrangements for supporting them were "inadequate".
While the manufacturer, Roche, had issued "clear guidance" that individual risk assessments should be conducted before prescribing, the committee said the MoD appeared to have interpreted this to include "desk-based" assessments using medical records rather than face-to-face interviews.
It said it was "deeply disturbing" that some personnel apparently preferred to throw away the Lariam they had been prescribed and run the risk of contracting malaria, rather than take the drug.
"If true, it is an indication that some in the armed forces have completely lost confidence in Lariam," the committee said.
"Lariam is a drug whose own manufacturers have laid down stringent conditions which must be met if it is to be prescribed safely.
"We see no reason to disbelieve the very strong anecdotal evidence that such conditions have been ignored in dispensing it to large numbers of troops about to be deployed."
The committee chairman Julian Lewis said: "It is our firm conclusion that there is neither the need, nor any justification for continuing to issue this medication to service personnel unless they can be individually assessed, in accordance with the manufacturers' requirements.
"And - most of the time - that is simply impossible, when a sudden, mass deployment of hundreds of troops is necessary."