Following the FIA's opening argument at its International Tribunal, Mercedes has hit back accusing the sport's governing body of hypocrisy whilst also pointing the finger at Ferrari.

Having claimed that the test was not undertaken by Mercedes but Pirelli, the German manufacturer's counsel, Paul Harris, referred to an email exchange between the FIA's race director Charlie Whiting and its own lawyer Sebastien Bernard following questions raised by sporting director Ron Meadows and team principal Ross Brawn on May 2 as to whether testing with a 2013 car was allowed.

On May 3, Bernard responded saying that Mercedes could use its 2013 car as, for the purposes of the test, it would not be seen as a competitor's car.

Whiting subsequently sent an email which read: "In my view any such testing would not actually be undertaken by competitors, it would be/could be argued that it was done by Pirelli. Would we be able to take this position?"

"Indeed we could take this position," replied Bernard, "it is not an undertaking from the competitor."

Harris claims that Mercedes undertook the test for reasons of safety. "We had safety concerns," he insisted, "as did our drivers, as did other teams."

Having avoided the question in Canada, Mercedes admitted that it regretted the decision to run its drivers, Lewis Hamilton and Nico Rosberg, in anonymous black helmets during the three-day test.

Claiming the move was made in the interests of "security", Harris said: "We acknowledge this aspect was bound to raise suspicion and this is regrettable.”

Though the FIA decided no further action was needed in terms of Ferrari's test with Pirelli, which saw Pedro de la Rosa driving a 2011 car, Harris insists that all is not what is appears, claiming, amongst other things, that the Italian team's test comprised more than 1000 kilometres.

"Our position is if we are wrong on interpretation of what Article 22 means and there was track running by us, such as we are in breach, it follows that Ferrari were also in breach," said Harris. "They ran their car on track and we argue their car followed substantially with the regulations I put the marker down.

"It does not follow that if Ferrari runs on track a 2011 car, that that 2011 car does not confirm substantially to either the 2012 or 2013 regulations," he continued. "There was only half-a-second difference between the 2011 cars and 2013 cars, showing the changes between 2011 and 2013 are minuscule in terms of performance."

Having revealed that Ferrari took part in a test with Pirelli at Barcelona in 2012, Harris claimed that if Mercedes is in breach of the regulations (Article 151C) for its 2011 car test, Mercedes cannot be for running a 2013 car.