The Conservative Party has won all six seats in Cornwall, wiping out Liberal Democrat representation in the county.
Lib Dem Andrew George lost St Ives to Conservative Derek Thomas by 2,469 votes in the last result declared.
The outcome has transformed Cornwall's political landscape from a Lib Dem stronghold in the 2005 election.
Analysis: BBC SW political correspondent Martyn Oates
If you look at the collapse of the Lib Dem vote it's been quite spectacular, with some seats in the South West dropping by almost 30%, but you should also bear in mind the Conservatives haven't only made gains at the expense of the Lib Dems.
In Plymouth, which is traditionally a Conservative/Labour contest, Labour has lost a seat to the Conservatives and the Tories have also held on to a seat Labour thought they were very well placed to gain - that could have something to do with the rise in the UKIP vote in Plymouth.
The St Ives constituency result was not declared until about 15.30 BST because ballot boxes from the Isles of Scilly have to be flown to the mainland.
Mr George told supporters: "There was nothing which we could do to counteract the tsunami which was taking place against us."
He described what had happened as a "national movement".
Having held the seat for 18 years he said he would "carry on fighting for the constituency" and would not "walk away".
Liberal Democrat Dan Rogerson, who lost the Cornwall North seat to Conservative Scott Mann, said: "It's been a really tough night for the Liberal Democrats.
"Some excellent colleagues have lost their seats. So it's a sad one for us, but political cycles come round again."
Conservative Sarah Newton retained her Truro and Falmouth seat with a 14,000 majority, up from just over 400 last time round.
She said: "We have demonstrated in five years substantial investment into Cornwall and opportunities for devolved power.
"So we have a good track record and people want us to carry on doing that."
Stuart Roden, Labour candidate for the seat, said: "We've massively increased our vote since last time and I think we've made a huge impact in the constituency.
"I'm desperately disappointed by the national picture, but I think we have made some real progress in Cornwall."