One lucky member of the public may have managed to land a place in the Big Brother house by getting their hands on the correct golden ticket, but the real winner has been Nestlé Rowntree.

According to the com­pany, sales of standard and chunky Kit Kat doubled during the two-week competition period, which ended at 10.20pm last night, with the company struggling to keep up with demand.

Graham Walker, sales communications manager, said: "We have seen national sales of Kit Kat literally ­double overnight as people up and down the country hunted out the remaining tickets. Our factory and supply chain teams were working flat out, 24 hours a day."

Walker added that retailers with special Big Brother displays had recorded an unprecedented sales increase of the confec­tionery of between 1,000 and 2,000%. "This has never been seen before," he said.

Nestlé Rowntree launched the promotion on 18 May by hiding 100 tickets in Kit Kat four-finger and single bars and Kit Kat Chunky, with the chance for one lucky person to gain entry into this year's Big Brother house.

Such was the frenzy around the promotion that unopened bars were sold on internet auction web site eBay, sometimes at more than 100 times their price.

The promotion will give a vital boost to the Kit Kat brand, which last year suffered from a 24% drop in sales [ACNielsen 52 w/e 1 October 2005].

It is the second time Nestlé Rowntree has struck gold by offering the chance to find a golden ticket in a chocolate bar.

In August 2005 it saw sales of its Wonka bars ­rocket on the back of a promotion offering the chance to win five tickets for a trip to the US linked to the remake of the film Charlie and the Chocolate Factory, in which Willy Wonka is the central character.