David Cameron has hailed the Newark by-election result as "very good for the Conservative Party" but he said the Tories needed to "work between now and the next election" to win back voters from Ukip, who came out second in the by-election.
The PM was speaking in Bayeux, France ahead of D-Day commemoration events.
Asked how he would win back support from Nigel Farage's party he acknowledged the challenge posed by Ukip:
"The job isn't finished yet but we are on the right track, let's stick at it."
More top news
Rain in the north tonight, cloudy and humid in the south
In an exclusive interview with ITV News, 100 metre world champion Justin Gatlin also said that booing at the World Championships "did hurt".
The 26-year-old had just given birth to her third child and was being transferred to a different floor when the tragedy happened.