Nigel Farage has said his lack of connections with the local area may mean he chooses not to run in Newark.
A by-election in the constituency was triggered after the resignation of Tory MP Patrick Mercer over a cash-for-questions scandal.
The Ukip leader told the BBC:
I know that winning one seat in Westminster would completely transform the landscape for us as a party in terms of our prospects.
What I've got to work out is, is it the right seat for me. And I just...my reservation in my mind is I haven't particularly got connections with the local area.
Nigel Farage believes efforts to discredit him and his party are failing - and the polls suggest he may well be right.
Almost one third of Britons think that Ukip is a racist party, according to a new ITV News/ComRes poll.