Mozilla is reported to be considering legal action against Dell, after it was revealed that the PC maker was charging customers in the UK a fee amounting to around $27 to install its free Firefox browser on new computers.

Sources told The Register of Mozilla’s plans just days after it learned that Dell was demanding a fee of £16 from UK-based customers who wished to have the browser pre-installed on new laptops bought from the company. The website was alerted by a Dell customer, who grabbed a screenshot of the additional charge. The non-profit group has now begun an official investigation into Dell’s policy, but it’s not clear if any legal action will result.

Mozilla is upset because its browser software, which is one of the most popular on the internet with around 500 million users worldwide, is supposed to be entirely free for people to use when carrying the Firefox brand name. Previously, Denelle Dixon-Thayer, Mozilla’s vice president of business and legal affairs, told the BBC that the organization had never struck a deal with any company to charge for its software.

“There is no agreement between Dell and Mozilla which allows Dell or anyone else to charge for installing Firefox using that brand name,” said Dixon-Thayer. “Our trademark policy makes clear that this is not permitted and we are investigating this specific report.”

Indeed, the relevant part of Mozilla’s terms of service explains this quite clearly:

“The Mozilla product must be without cost and its distribution (whether by download or other media) may not be subject to a fee, or tied to subscribing to or purchasing a service, or the collection of personal information.

If you want to sell the product, you may do so, but you must call that product by another name — one unrelated to Mozilla or any of the Mozilla Marks.”

However, Dell argues that it isn’t charging fees for Firefox at all – rather, it says that the charge is for the time and labor involved in installing the browser onto its machines. That argument may give it some, albeit shaky, legal ground to stand on, but it’s not one that’ll generate much sympathy. At the most, Firefox takes around ten minutes to install, which means that Dell is charging around $165 an hour to load its PCs with free, open-source software.

Smaller computer service providers have been guilty of tricking people into paying for free software in the past, but this is the first time we can recall a major tech company operating along what appears to be similar lines. Dell may or may not be acting illegally, but the fact it’s asking so much to perform a relatively simple service (and one that no other PC makers charge for) is a rare case of negative publicity for an otherwise well-respected company.