A row broke out today after Conservative Party co-chairwoman Baroness Sayeeda Warsi linked the rise of the UK Independence Party (Ukip) with the decline of the far-right British National Party.
Ukip are tipped to do well as the results pour in this morning, with the BNP falling further behind.
But Lady Warsi appeared to suggest the number of candidates fielded by the eurosceptics had risen in line with a fall in the number standing for the BNP - a link with provoked Ukip's spokesman to brand her "a bitch".
Speaking on the BBC's election night coverage, Lady Warsi said: "Where Ukip is fielding candidates this time that the BNP did last time but they're not this time, I think that will have an impact."
She added: "There are members of Ukip who are from all sorts of political parties, but it is an interesting mix there in terms of the number of candidates."
Ukip spokesman Gawain Towler vented his anger at Lady Warsi's comments on Twitter, calling her a "bitch" to his 1,700 followers, some of whom criticised his "unparliamentary language".
The spokesman quickly deleted the post and and apologised, tweeting: "Deleted, out of order on my part".
He later added: "Shouln't (sic) have said that, apologise."
Mr Towler later accused Lady Warsi of making "completely pre-scripted" remarks as part of a "planned insult", adding: "Obviously they see us as a threat."
But he told the Press Association: "While her comments were contemptible, mine were out of order and I apologise fulsomely."
Baroness Warsi has come under fire from fellow Conservatives. Raheem Kassam, from the Bow Group, said her remarks were "irresponsible but sadly, entirely predictable".
He added: "It is high time the Conservative Party started tending to its grassroots, rather than demonising other right-wing parties and comparing them to Nick Griffin. Then and only then will the Tories secure the grassroots support they need to deliver conservative policies across the country with an effective and representative mandate. If the party wishes to become more electable, it must move voters to the centre-right, rather than seek to move further left itself."