78-year-old Mr Brar, who commanded the Operation Blue Star in 1984, was on a private visit to London with his wife Meena when the suspected Khalistan sympathisers attacked the couple.
He sustained serious injuries while his wife escaped unharmed and was instrumental in raising an alarm to call the police.
During a hearing on Tuesday, prosecutor Annabel Darlow told the Southwark Crown Court that the victim was deliberately attacked because of his role in the Golden Temple operation.
"Brar is now retired but during his career as a general in the Indian Army oversaw a number of military operations which have made him a target for Sikh extremist groups," Darlow was quoted as saying by the BBC.
"This was no random attack. This was a highly premeditated assault by people who thought about what they were doing and planned it," Darlow said.
The trial of two Sikh men and a woman accused of stabbing Mr Brar opened on Tuesday, nine months after the attack.
Mandeep Singh Sandhu (34), Dilbagh Singh (36) and Harjit Kaur (38) pleaded not guilty to the charge of "unlawful wounding with intent to do grievous bodily harm" in relation to the attack, which took place on September 30.
The jury heard that when the defendants found that Lt Gen Brar was in London they made two reconnaissance missions over two days to check out his movements.
On the night of the attack Kaur tailed Mr Brar and his wife, following them into a casino and then a restaurant. She also got onto a bus with the couple, the BBC reported.
"She played a crucial role, silently and unobtrusively following this couple who were unaware they were being followed by a woman who was relaying information to four men that were bent on attacking Brar," Darlow said.
Mr Brar was attacked by a gang of four men as the couple made their way back to the hotel.
The victim has survived several assassination attempts and still receives death threats, as the military operation "has not been forgotten", the court heard.
A fourth key accused, 33-year-old Barjinder Singh Sangha, had pleaded guilty to the charge of "unlawful wounding" and will be sentenced at the end of the trial.
All four co-accused have been in judicial custody for their alleged part in the stabbing.