• Swiss writes to Fifa’s 209 members protesting his innocence • Letter itself seems to have breached terms of Blatter’s ban

Sepp Blatter has likened the Fifa ethics committee process that could lead to him being banned from football for years to the Spanish inquisition in a letter that itself appears to breach the terms of his suspension.

The Fifa president had resolved to carry on his tradition of writing an end of year letter to all 209 members of the governing body despite being provisionally suspended for 90 days over a £1.35m “disloyal payment” to Michel Platini, the suspended Uefa president.

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Although it is not on Fifa-headed paper, it is understood that in writing to all 209 FAs around the world Blatter has breached the terms of his provisional ban from all football-related activities. His spokesman, Klaus Stöhlker, said Blatter was unconcerned about whether he had technically breached the terms of his ban. “He is more concerned about the fairness of the hearings and the outcome,” he said.

In the letter Blatter is understood to have written: “Although I have been suspended I am not isolated and will certainly not be silenced.”

As he prepares to face the ethics committee on Thursday, with the investigatory arm having requested a life ban but a suspension of six to seven years seen as more likely, Blatter is understood to have written that he was “bewildered by the insinuations and allegations brought against me by the investigatory chamber of the ethics committee”.

The 79-year-old Swiss, who this year resolved to stand down as Fifa president following the US indictment of what prosecutors described as a “World Cup of fraud”, insisted the process by which Platini received the payment nine years after it was originally due as part of a gentleman’s agreement between the pair was above board.

“However, the way in which the investigatory chamber of the ethics committee has communicated on the current proceedings, demanded the maximum penalty and reinforced public prejudgment has reached a tendentious and dangerous dimension,” he added. “These proceedings remind me of the inquisition.”

It was Platini’s lawyer who first revealed that the investigatory arm of the ethics committee was seeking a life ban for both men over the payment, which was made in 2011 weeks before Blatter was re-elected for a fourth term.

The pair face charges including corruption, conflict of interest and noncooperation. Blatter’s case will be heard on Thursday with Platini’s following on Friday, with a decision expected on Monday next week.

Blatter also says in the letter, seen by the Guardian that he has always “faced up to the challenges with honesty, respect and fair play”. He says he has maintained the values passed down to him by his parents: “Never accept any money which you have not earned, always pay off your debts.

“I will continue to fight for my rights – and at the end of this week, I will present my case before the adjudicatory chamber with great conviction and a strong belief in justice”.

Blatter also faces a Swiss criminal investigation over the £1.35m payment and Platini has been interviewed as “someone between a witness and an accused person”. Both men have denied wrongdoing.

In the letter, Blatter again reaffirms his innocence. “In the current case, the adjudicatory chamber of the ethics committee must pass judgment on the legality of the bill for two million Swiss francs – stemming from the 1998 agreement between Fifa and Michel Platini – and whose payment [of the remaining amount] was only requested in 2010-11,” he says.

“I can assure you that it was legal because it was based on a verbal agreement. And agreements must be adhered to. This payment was put through the full administrative process, the correctness of which was confirmed by all competent Fifa bodies – including the congress.”