A number of non-UK residents have been handed postal votes and polling cards for the upcoming EU referendum, the Electoral Commission has admitted.
The election watchdog blamed the problem on software used by some local authorities in England and Wales, but said it was still working to establish the numbers affected.
This month’s referendum on EU membership excludes non-UK nationals and the Electoral Commission said that any wrongly issued postal votes will be cancelled, while voters with incorrectly issued polling cards will be unable to vote.
In a letter co-authored with veteran backbencher Bernard Jenkin, Duncan Smith accused the Electoral Commission of “abdicating responsibility”, and questioned where it would be able to verify the nationalities of voters who had registered to vote.
“We believe the British public will be as shocked as we are to discover that the integrity of the franchise for this long-awaited referendum with profound consequences for the future of our nation is being protected in such a lax manner,” Duncan Smith and Jenkin wrote.
The commission responded that if staff have concerns about nationality, they can require individuals to provide evidence, such as a birth certificates, or certificates of naturalisation.
And where it has doubts over residency, it can request checks of Home Office records.
Knowingly providing false information while registering to vote can bring six months imprisonment or an unlimited fine in England and Wales or a of up to £5,000 in Scotland.