More than 166,000 people have backed the petition to stop travel companies raising their prices during school holidays which has triggered today's MPs debate.
The online campaign received a huge boost in support after a Facebook post by an angry parent complaining about being "ripped off" by steep rise in holiday prices outside term time went viral.
Paul Cookson, 41, said he was "sick to death" of the practice after being quoted £999 for a holiday that would have cost £699 during the school year.
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State Department spokeswoman Heather Nauert said Pence "was ready to take this opportunity."
Opposition activists said government forces have brought in more reinforcements in recent days.