The Catholic writer and broadcaster has been speaking after Mark Reckless, who defected from the Conservatives, regained his Rochester and Strood seat.
UKIP now has 2 MPs in Parliament and leader Nigel Farage says it means "literally anything could happen" at next year's general election.
He's also suggested that other Conservative MPs are ready to join his party.
Results:
Mark Reckless (UKIP) 16,867 (42.10%)
Kelly Tolhurst (Conservative) 13,947 (34.81%)
Naushabah Khan (Labour) 6,713 (16.76%)
But Ann Widdecombe's not impressed. Speaking to Premier she said: "It was not unexpected. The margin wasn't terrific. Consistently on the ground we've been told that people were lending their vote to UKIP, but in a general election would vote for a party which is capable of government which, of course, UKIP isn't.
"I think that's the whole point. What happened last night isn't going to change the government.
"What happens in May can."
Mary Reckless beat his former party by almost 3,000 vote but just a 4% swing could see the seat going back to the conservatives.
Prime Minister David Cameron said: "This result was the closer than the forecasters predicted and I want to congratulate Kelly Tulhurst (Conservative candidate) on such a positive and strong campaign.
"Let me say I'm absolutely determined to win this seat back at the next general election."
Listen to Ann Widdecombe speaking to Premier's Lisa Mainwaring: