In 2017 every seat in South Yorkshire was won by Labour. But now the region is an election battleground, partly because many voters in Labour-held areas backed Brexit.
Our political correspondent Joe Pike went to meet some of the candidates in the constituency of Doncaster North.
And here is the full list of the candidates who are standing in the Doncaster North constituency. The polls open at 7 am tomorrow and they close at 10 pm.