Oscar-winner Kevin Spacey appears in London court on sexual assault charges

Actor Kevin Spacey said on Thursday he was "crushed" when he was accused of sexual assault, as he began giving evidence in a London court.

The Oscar-winner told jurors at Southwark Crown Court that he could not believe that one of the complainants, who alleges Spacey assaulted him on up to 12 occasions, would "stab me in the back".

The 63-year-old is standing trial on a dozen charges of sex offences against four men between 2001 and 2013 when they were in their 20s and 30s. Spacey has pleaded not guilty to all 12 charges.

The four accusers have said Spacey aggressively groped them and in one case performed oral sex while they were passed out, with the prosecution calling him a "sexual bully".

His lawyer Patrick Gibbs told the jury on Thursday that the complainants had reimagined consensual encounters "with a sinister spin" or, in some cases, simply "made up" their accounts.

Spacey, wearing a grey suit, white shirt and light blue tie, entered the witness box on Thursday and was asked about one of the complainants, who alleges the actor repeatedly grabbed his "private areas" when they were alone.

The lawyer, Gibbs, asked about his relationship with the man, to which Spacey said: "I liked him greatly. We had a good time together. We laughed a lot."

The actor described the complainant as "funny and charming and flirtatious". Asked if he himself was flirtatious, Spacey replied: "Yeah. I'm a flirt, I'm a big flirt."

He said that as his relationship with the complainant developed over time "it became somewhat sexual".

Spacey denied that it was non-consensual or aggressive, saying: "It didn't happen in a violent, aggressive, painful way. It was gentle and it was touching and it was, in my mind, romantic."

He also said: "We never had sex together because he made it clear that he didn't want to go any further and that happens at times and you just respect how far someone wants to go."