He also told the court that he had been sexually abused as a child.
The BAFTA award-winning comedy actor told the jury at Maidstone Crown Court that he had been “arrogant” for looking at child porn on his computer and said he realised there was no excuse.
But he stressed he was not a paedophile.
“I would like to make it clear that I am not taking the crime I committed lightly,” he said under questioning from his counsel, David Whitehouse QC.
“I did it in an arrogant way. I know who I am. I did a very arrogant thing not to think that the law applied to me.”
Referring to his arrest, he said: “They (the police) wanted to convict me on the basis that I had an abnormal interest in children. That I was a paedophile. I am not.”
He added: “I realise there is no excuse for it. You cannot do this and have a reason for it. I knew this when I made my admissions.”
He admitted looking at adult porn on the internet.
“I look at a lot of porn. I am afraid that doesn’t make me look good, but I have done it for years,” he added.
He also claimed that when he was young he had been sexually abused.
“Are you telling us that as a child you were subject to sexual abuse?” asked the judge.
“Yes,” replied Langham.
Earlier in the day, the jury were instructed by the judge to find Langham not guilty of four of the indecent assault charges he faces.
He still faces six other counts of assaulting a teenage girl and 15 child pornography offences.
The star of the BBC comedy The Thick Of It denies the accusations.
The case was adjourned until 9.45am this morning.