A dad in Portugal had a nasty surprise when his 17-year-old son used his eBay account without his knowledge to place a £21,000 winning bid for a server previously used by WikiLeaks.

Bahnhof, a Swedish internet service provider which had hosted WikiLeaks for about eight months in 2010, were selling the server to raise money for two charities: Reporters Without Borders and the 5th of July Foundation, a digital rights group.

The company's CEO John Karlung, said that soon after the auction closed yesterday, he received a message from the buyer, saying that his son had the item unbeknownst to him and he wanted to cancel the deal.

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According to eBay, the boy initially bid $10,200 (£6,500) for the server, back on 7 September. He then bid seven more times, winning the auction with a $33,000 (£21,000) bid.

Bahnhof said it had wiped any data from the server and was selling it as an historical artefact.

WikiLeaks, which would not have benefitted from the sale, claimed that Banhof had exaggerated the significance of the server, and tweeted their disapproval.

"We do not support Bahnhof exploiting the privacy and good name of their clients for marketing purposes," the organisation said on on their Twitter account on 2 September.

In emails to Karlung, the father, an industrial maintenance worker who lives outside of Lisbon, explained: "My son is 17 years old and is crazy about conspiracy theory".

Speaking to Wired, he added that he was "speechless" when he learned about his son's winning bid, but he was yet to discuss it with him. "A more serious conversation will be had tomorrow," he said.

Banhof agreed to cancel the deal and the server will now be sold to the second highest bidder for $32,900 (£20,800).