Lewis Hamilton’s chances of being penalised as a result of the McLaren-Ferrari spying scandal increased substantially yesterday after further damaging allegations about who knew what and when at McLaren were reported in the Italian press.

Ron Dennis, the McLaren team principal, has always maintained that only one man in his company – Mike Coughlan, the designer who has been suspended – knew about the 780-page dossier of technical information stolen from Ferrari.

However, Dennis’s contention, which is critical to McLaren’s defence against a charge by the FIA, the sport’s governing body, of “fraudulent conduct”, is being steadily undermined as more people are alleged to be involved.

In the High Court in London last week it emerged that Jonathan Neale, the McLaren managing director, knew about the dossier, though exactly when has not been confirmed, and, on Saturday, La Repubblica, the Italian daily newspaper, reported that several other team members had also been shown the documents.

The paper quoted from a confidential affidavit that Coughlan handed over to Ferrari lawyers in London last week in which he was asked to give details of everything he knew about the documents. It says Coughlan admits in his sworn statement that he had Ferrari technical drawings and internal documentation in his possession and that he had shown them to several other people in the team apart from Neale.

La Repubblica said Coughlan reported that all the McLaren employees who saw the classified material reacted in the same manner, distancing themselves from what they had seen and advising Coughlan to destroy the papers.

It has been alleged that Coughlan originally got hold of the dossier from Nigel Stepney, the disaffected former Ferrari mechanic. But Coughlan does not confirm this in his statement. He is quoted only as saying he received the papers via an “express courier” mail service. Stepney is the subject of a criminal investigation in Italy and has denied all allegations against him.

There are also big question marks over McLaren’s original contention that Coughlan received the papers from Ferrari at the end of April, amid claims by lawyers for Ferrari that he may have been sent more classified material in May, and suggestions by the FIA itself that McLaren may have had the material as early as March.

Either way the picture emerging is increasingly worrying for Hamilton, who leads the World Championship at the halfway point in his rookie season by 12 points from Fernando Alonso, his McLaren teammate. The FIA has several sanctions available to it, should McLaren be found guilty at an extraordinary hearing of the World Motor Sport Council scheduled for Paris on Thursday week. These range from a reprimand to a fine, to docking of constructors’ or drivers’ points or exclusion from the championship.

The FIA charge relates to McLaren’s “unauthorised possession of documents and confidential information” belonging to Ferrari and “information that could be used to design, engineer, build, check, test, develop and/or run a 2007 Ferrari Formula One car”. The FIA will want clarification on how McLaren discovered that Ferrari were using a moveable aerodynamic device on the “floor” of their cars, something that was the subject of a rule change after McLaren asked the FIA to decide on its legality. It will also want evidence from McLaren that the team did not benefit from their knowledge of Ferrari race strategy options thought to be in the dossier.

One of the biggest problems for McLaren is that once Coughlan had read the documents in his possession, it is impossible to prove one way or another whether the knowledge he gained influenced any decisions he might have taken about this year’s campaign, next year’s car or anything else he might have been working on.