Judge Geoffrey Rucker was told it was also very unlikely the victim would now find a Tamil man willing to marry her. The attack had brought tremendous shame on her family and this had added to the emotional trauma that the Sri Lankan girl, who has been a virgin, had suffered.
'The shame of what has happened to her will live with her forever,' Philip Bennetts, for the prosecution, said at the Old Bailey. 'It has had immense cultural effects.'
Scott Twiss, 18, was sentenced to eight years' detention for the rape at the off-licence in south London last November.
The court was told that Twiss and his friend David Chaston, 19, burst into the off-licence brandishing guns.
After they took the pounds 15 takings from the till, Chaston forced the girl, who had been sitting outside in her brother's car, into the shop.
The girl was then raped by Twiss as Chaston stood guard and her brother, who had earlier been beaten up, was forced to watch.
Her brother believed he would be shot if he intervened, but pleaded with Twiss.
'The brother begged him not to. She also pleaded with him but their entreaties fell on deaf ears,' Mr Bennetts said.
'She screamed, struggled and cried. All to no avail.'
The court heard that during the raid the brother had managed to press a silent alarm that went straight to a police station and the pair were caught by officers as they tried to leave.
Twiss, of Rotherhithe, south-east London, admitted rape and robbery and a related firearms offence.
Chaston, also of Rotherhithe, admitted robbery and possessing an imitation firearm with intent, but was cleared by a jury of rape. He was ordered to be detained for four years.
Richard Kerry-Hughes, defending Twiss, said the day before the raid his client had for the first time taken a cocktail of the drugs ecstasy and valium.
He added: 'Twiss believes the rape never would have happened if he had not taken those drugs.'