If you thought mall Santas had a magical power to make little kids cry BEFORE, this takes it to a whole different level.

A mall Santa at the Brent Cross Shopping Center in London is going to give kids LIE DETECTOR TESTS this week . . . to find out if they're actually naughty or nice.

Kids who go to the mall from Wednesday through Friday will get a surprise lie detector test with questions like, "Have you been good this year?" and, "Do you always clean your bedroom?"

Afterward, the kids and their parents will get a report on how the kid performed on the test

The mall says they're doing it to, quote, "instill a sense of honesty among children."  There's no word on whether the parents will have to give CONSENT to have their kids hooked up to the polygraph.


photo credit: getty images