Is UKIP now a threat to Labour seats in the North?
UKIP's new Leader, Paul Nuttall, says his party can gain at least 10 seats at the next election.
And he hopes to do it at the expense of Jeremy Corbyn's Labour party which he says doesn't represent working people anymore.
Some Labour MPs, particularly those in working class northern seats, are getting jittery.
Sunday Politics reporter Ellie Price has been to Barnsley to investigate.