Former Tory MP Louise Mensch appears to have conceded Labour will win the by-election in Corby and said the defeat was entirely her fault.
Mensch triggered the poll in the midlands seat after she decided to quit parliament after just two years in order to move her family to New York to be with her husband.
"Christine [Emmett] and her team did an incredible job in the most difficult possible circumstances. I know she will one day make a wonderful MP," Mensch tweeted on Thursday evening just after polls closed at 10pm.
"Election result will not be a verdict on either Christine, or the Conservatives, but only on the decision I took to step down mid-term.
She added: "Though I had to resign to unite our family, there was large & entirely understandable local anger. I wish I had been able to see out my term."
The result of the Corby by-election is due to be announced on Friday. Bookmakers William Hill have made Labour the almost unbackable 1/100 favourites to win the seat from the Conservatives.