Shadow home secretary Diane Abbott has wrongly claimed 16-year-olds can fight for their country.
In a video posted on Facebook calling for the voting age limit to be lowered from 18, she says: "I believe in votes at 16. If you are old enough to fight for your country you are old enough to vote."
A teenager can sign up at the age of 16 but they would not be able to go into combat until they are 18, according to the Ministry of Defence (MoD).
A spokesman said: "You can join at 16 but between 16 and 18 you will be training but not deployed. You need to be 18 to be deployed."
Ms Abbott was speaking after a call for 16 and 17-year-olds to be able to vote in UK parliamentary elections, local elections and referendums was debated in the Commons earlier this week.
Debate on the proposal was adjourned, with Labour's Jim McMahon asking for it to return on 1 December, although it is unlikely to receive time for further consideration on that day.
During this year's General Election campaign Ms Abbott said she "mis-spoke" when she gave a string of incorrect figures during a radio interview about policing policy.
She stumbled over the cost of plans to put 10,000 extra police on the street in awkward exchanges with LBC's Nick Ferrari.
In one attempt to come up with the bill for the flagship policy, officers would have earned just £30 while a second go left them with £8,000.
Ms Abbott's assessment of how many new officers would be recruited in the first 12 months of the four-year plan ranged from 25,000 to 250,000.
She later told BBC Two's Daily Politics: "I do know my figures. I did seven interviews that morning and that was the seventh and I mis-spoke, but I do know my figures."
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