Commander Dizaei denies all the charges
Met Police Commander Ali Dizaei, who is accused of framing a web designer for assault, feared he was being "targeted" by his own force, a court has heard.
Southwark Crown Court heard an argument started in July 2008 when Waad Al-Baghdadi, 24, demanded £600 for work on Mr Dizaei's personal website.
Mr Dizaei, 47, denies assaulting and falsely arresting the businessman.
He said he did not answer police questions about the alleged assault as he had no trust in the force's inquiry.
Mr Dizaei also denies misconduct in public office and perverting the course of justice.
The commander and Waab al-Baghdadi rowed over money for a website when they met by chance at the Persian Yas restaurant in Kensington, west London.
Mr Dizaei denies assaulting and falsely arresting the businessman who he then left facing prosecution.
He said he refused to answer police questions when he was interviewed about the alleged assault because he thought he was being targeted by the Met over his support for Assistant Commissioner Tarique Ghaffur in his race discrimination claim against former Commissioner Sir Ian Blair.
The officer, who is president of the National Black Police Association (NBPA), told the jury he feared his telephone was being tapped, that he was being followed, and that he was concerned about his personal safety.
Mr Dizaei said officers refused to show him CCTV footage of the incident and a transcript of his 999 call despite repeated requests by his lawyers before the police interview.
The officer added that he was "nervous" about "the way the allegation was proceeding", with the "drip-feeding" of information in a bid to get him "locked in to one answer".
Asked by Peter Wright QC, prosecuting, if his fears were "nothing more than a smokescreen" to hide discrepancies between his account of events and CCTV footage, Mr Dizaei said: "No, they're not.
"At the time I had no trust or confidence in the investigation," he added.
"It reinforced my suspicions that there was something not quite right there.
"I remain a loyal police officer. I love everything about this country for giving me the opportunity to aspire and to achieve my aspirations.
"To suggest that I would throw all that away because Mr al-Baghdadi disrespected me over his website... I'm sorry, but the lines for me just don't join up."
The trial continues.