A computer expert has denied forging documents to falsely suggest he is the creator of Bitcoin at the start of his evidence at the High Court.

Dr Craig Wright claims he is “Satoshi Nakamoto”, the pseudonym of the person widely credited with founding the cryptocurrency in 2008.

The computer scientist is being sued by the Crypto Open Patent Alliance (Copa), a non-profit group including cryptocurrency firms, which has accused him of lying and forging documents to suggest he is the pseudonymous figure.

Dr Wright is denying the claims in a trial in London, and in the first of several days of his giving evidence, said he had not forged any documents.

On Tuesday, he was asked by Jonathan Hough KC, representing Copa: “Have you ever forged or falsified a document to support your claim to be Satoshi Nakamoto?”

Dr Wright replied: “No.”

Mr Hough asked: “Have you ever knowingly presented a forged or falsified document to support your claim to be Satoshi Nakamoto?”

Dr Wright replied: “I have not.”

Copa has accused Dr Wright of telling a “brazen lie” and creating an “elaborate false narrative” about being Satoshi and using “forgery on an industrial scale” to substantiate his claims.

Dr Wright denies the allegations, and when asked by Mr Hough about whether he forged one document on Tuesday, he replied: “If I forged that document, it would be perfect.”

Barristers representing the Australian, who moved to the UK in 2015, have said that he had the relevant skills and knowledge needed to create Bitcoin and write the document which led to its founding, which he began drafting in 2007.

The document, known as the Bitcoin white paper, was released under Satoshi’s name, with the pseudonym last heard from in 2011.

After he was first linked with being Satoshi in late 2015, Dr Wright publicly claimed to be behind the figure in May 2016.

He said in written documents that he “did not want to be revealed” and wished to “remain in the background”, with his public naming leaving him feeling “violated and deeply pained”.

The court heard on Tuesday that the Satoshi pseudonym was inspired by the Japanese philosopher, Tominaga Nakamoto, with written submissions from his barristers stating that he had a “deep interest” in Japanese culture and had “adopted various Japanese pseudonyms” throughout his life.

Dr Wright, wearing a pale blue suit, also claims he had access to the email accounts used by the pseudonym but now no longer had it.

On Tuesday afternoon, Dr Wright’s barrister, Lord Grabiner KC, criticised the “extremely oppressive” conditions during the trial in the Rolls Building, which has been affected by high temperatures inside the packed courtroom.

Large fans have been used during breaks in the trial to try and regulate temperatures.

He said: “The working atmosphere in this room is extremely oppressive and is not a great advert for the system we are trying to run here.

“There is no air in here, it is intolerable. I am not sure what, if anything, can be done about it.”

In response, judge Mr Justice Mellor said he hoped to move the trial to a cooler courtroom by Friday, saying he would transfer to a different room “at the drop of a hat” if one became available sooner.

The issues are thought to be connected to a power outage at the building last month, with the judge joking that those inside the courtroom will have lost “quite a bit of weight” by the end of the trial, which is expected to conclude next month.

The judge will issue his decision in writing at a later date.