Ukip leader Nigel Farage conceded his party had been defeated during the by-election, but hailed the result as Ukip's "strongest ever by-election performance".
Speaking after the result, Mr Farage said: "I think there'll be an awful lot of Conservatives with a majority of less than 10,000 who will look upon this result in sheer horror."
But he admitted he would have liked to have done better in Newark.
"Yes, I mean the majority's halved, but nonetheless for Ukip it's still a good night's work," he said.
More top news
The former head of the Diplomatic Service breaks down the hidden meanings behind Theresa May's letter to Donald Tusk
The storms that struck Texas and Oklahoma late on Tuesday brought tornadoes, tennis ball-sized hail and powerful winds.
Samantha Baldwin, 42, and her sons Louis Madge, nine, and Dylan Madge, six, haven't been seen for two days.