[El Car]

It doesn't have to be quashed, the result doesn't bind anyone to any action since it was legally no more than a mass opinion poll. The government could easily use the 75% + 60% conditions to say the result wasn't enough to justify exiting the EU. They won't though because it would be political suicide and if there's one thing that's generally true of politicians in the public eye it's that they care a hell of a lot more about their political career than the good of the country.