As a result of her complaint, she received an official apology and two officers were disciplined.
But when she applied for compensation from the Criminal Injuries Compensation Authority (CICA), which covers England, Scotland and Wales, she was told the standard compensation would be cut in her case to £8,250.
The authority told her the reason for the reduction was that "the evidence shows that your excessive consumption of alcohol was a contributing factor in the incident".
The woman described receiving the letter as "like being slapped in the face".
"It was just so cruel and unthinking and so wrong because there is nothing you can do to prevent yourself being raped. It is not illegal to go out and have a drink, it is illegal to rape somebody," she said.
Her solicitor, Debaleena Dasgupta, said she had been "appalled" by the decision.
"It was immoral. My immediate reaction was there has got to be some way to fight this."
Her client has now won the full £11,000 after Ms Dasgupta successfully argued that regarding alcohol consumption as a contributing factor in rape cases was unfair because it implied the victim had been responsible for being raped.
Lisa Longstaff, of Women Against Rape, said the original decision by the CICA was symptomatic of the "blame culture" experienced by rape victims.
"It used to be that they were always blamed if they were wearing a short skirt, today it's that they were drinking," she said.
"It's very important for women who've been victims of rape to get compensation because often it's the only acknowledgement you are going to get that you have been a victim of crime, given that the conviction rate in this country is only 6%."
The CICA told the BBC that during the past 12 months, 14 other rape victims had had their compensation awards cut because they had been drinking.
It has issued a statement acknowledging it should not have happened in any case and confirming it is not its policy to reduce compensation for rape victims because of alcohol consumption.
A spokesman for the authority said: "We have just completed a review of our staff instructions, operating procedures and structure to ensure greater consistency in decision making."
The Ministry of Justice also said it was not its policy to "reduce the level of award to a victim of rape due to alcohol consumption.
"This stance supports our view that a victim of rape is not in any way culpable due to alcohol consumption."
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