Matthew Lewis has been thrown out of the party (PIC: Staffordshire Sentinel News and Media)
Kate and Gerry McCann have condemned a Conservative activist who boasted about dressing up as Madeleine McCann at a party, calling his actions "offensive".
Matthew Lewis has now apologised "unreservedly" to the McCanns. He was expelled from the party after telling friends of his New Year party exploits.
Tory chairman Caroline Spelman said the Conservative Future activist's actions were "completely unacceptable".
Madeleine was three in 2007 when she vanished during a holiday in Portugal.
Despite a worldwide hunt, there has been no trace of her since.
In a statement released on Friday, Mr Lewis said: "I unreservedly apologise to Mr and Mrs McCann for my actions.
"I completely regret my behaviour that night and since, and cannot express how sorry I am for the incredible hurt I have caused.
"Whilst my actions were not meant to be malicious, I fully understand the pain they have brought."
Mr Lewis, who is believed to studying in London, told friends on the Facebook website that he planned to attend a party dressed as Madeleine McCann.
He said his costume would include "pink pyjamas, a teddy bear and a vial of fake blood".
After the party, Mr Lewis used the website to tell another Conservative Future member that "there was a brief moment when I thought I might have gone too far with elements of the costume but it was OK".
Mr Lewis was listed by Conservative Future as its branch chairman in Staffordshire although he is reported to have resigned from the position last month.
Staffordshire Conservative Future's website now lists the post of chairman as "vacant".
He was pictured campaigning alongside Tory leader David Cameron during last year's Crewe and Nantwich by-election.
A spokesman for the McCanns said his actions were "offensive almost beyond belief".
Kate and Gerry McCann are demanding an apology
"His actions are not only disgraceful in themselves, they will also cause great hurt to Kate and Gerry," he said.
"It is a complete disgrace that Madeleine's name and image should be made fun of in this way."
But the spokesman praised the "swift and appropriate" action taken by the Conservatives against Mr Lewis.
In a statement, Conservative Central Office said there was "no place for this sort of person in the party".
"This offensive behaviour is not only shocking but intolerable and completely unacceptable," Mrs Spelman said.