Ukip has suffered a collapse in its vote, with many people who backed the party in 2015 switching to the Tories or Labour.
Early results saw the party's vote down by around 13% on 2015, when under Nigel Farage it secured a 12.6% share of the national vote but just a single MP.
Pressure will increase on Ukip leader Paul Nuttall if the party's vote share does not improve as further results come in, particularly if he fails in his second attempt this year to secure a Commons seat.
Mr Nuttall, who is standing in Boston and Skegness, failed to enter Parliament in the Stoke Central by-election in February.
An indication that it was going to be a difficult night for his party came in Sunderland, which a year ago provided an early sign that the European Union referendum was going to result in Brexit.
In Houghton and Sunderland South, Ukip's vote was down 15.78%, in Sunderland Central it was down 14.25%, and in Washington and Sunderland West it was cut by 12.85%.
Former party leader Mr Farage insisted that Ukip could benefit if - as an exit poll predicted - the country faces a hung parliament.
He told LBC Radio: "If the result of this tonight is that we finish up without a government with a clear majority pushing for Brexit, then a huge gap opens in the political landscape for Ukip once again."
But he said officials in Brussels "will have looked at the exit polls and be cheering very loudly because right now, if we believe the exit polls, Brexit is under a bit of threat".
Mr Nuttall tweeted: "If the exit poll is true then Theresa May has put Brexit in jeopardy. I said at the start this election was wrong. Hubris."