The Lagos Analysis Corporation (Lancor) has filed suit against the One Laptop Per Child (OLPC) foundation for alleged patent infringement.

The suit centres on Lancor's patent for a four shift-key keyboard, which the company claims has been illegally reverse-engineered by the OLPC for its XO laptop. The extra shift keys are useful for typing in multiple languages.

"They can either do the right thing, and sit down like they sat down with other companies and negotiate a royalty, or they can just stop," Ade Oyegbola, founder and chief executive of Lancor, told the Boston Globe.

Oyegbola claimed that Lancor developed the keyboard over seven years to handle the diverse languages spoken in Nigeria. By doubling the number of shift keys users can generate accents, tildes, umlauts and other symbols more easily.

Robert Fadel, director of finance and operations at the OLPC foundation, said in a statement: "OLPC, a non-profit educational organisation, has heard that Lancor has sued in Nigeria, but has not seen any legal papers related to the suit at this time.

"OLPC has the utmost respect for the rights of intellectual property owners. To OLPC's knowledge, all the intellectual property used in the XO Laptop is either owned by OLPC or properly licensed.

"Until we have a copy of the claim, and have had time to review it, we will not be commenting further on the matter."

The OLPC has had a rocky relationship with Nigeria, despite early enthusiasm. The country ordered the XO laptops last year, but cancelled last month in favour of Intel's Classmate PCs.

Speaking to the BBC, Nigerian education minister Dr Igwe Aja-Nwachuku made the not unreasonable point that there are more pressing needs in Nigeria's impoverished schools.

"What is the sense of introducing OLPC when [children] do not have seats to sit down on and learn? When they do not have uniforms to go to school in? Where they do not have facilities?" he asked.