Mark Malone, 30, is accused of stabbing Jeff Akers, 50, so forcefully that knife sliced through one of his ribs and caused a fatal hemorrhage.
"Such was the force used in the attack that the knife sliced through one of his ribs and caused a fatal hemorrhage," said the prosecutor, Ann Cotcher.
She told the court that witnesses had seen Malone earlier in the day waving a knife in the air and said he "gave the impression that he was angry, that he was on a mission".
"It was a totally unprovoked attack by Mark Malone," Cotcher told the court, "and the only possible motive [was] homophobia, a dislike of homosexuals.
"It was a deliberate attack and it was a ferocious attack."
Prosecution: Gay man died in 'deliberate' 'homophobic' attack [contd.]
Malone claims he had drunk a bottle of vodka on the day he stabbed Akers and claims he has little memory of the attack, Cotcher explained.
He told police when he turned himself in two days after the attack that he became involved in a scuffle when Akers made advances on him.
The court heard that the toilet was a well-known venue for homosexuals who would meet there for sex.
Unemployed Malone used to go fishing in the area, a local beauty spot beside the Thames, Cotcher said.
After the attack, Malone confessed to his brother-in-law that he had stabbed someone, and told him he hoped he died, Cotcher said.
He turned himself into police two days later.
He told police at the time that he had no issues with the gay community and he was not an angry person.
Jurors will be asked to decide if the stabbing was deliberate or an accident.
Source: Man died in 'homophobic' stabbing | BBC News
'Accountant died after being stabbed in homophobic attack' | Daily Mail