After all this, however, Pakistan has done nothing. They have virtually rejected the evidence, and are calling it 'information, not evidence!' Pakistan's NSA grudgingly confirmed that the lone terrorist captured, Ajmal Amir 'Kasab,' was a Pakistani, for which he was promptly fired!
Now, India is considering more options. While the US and the UK can only do so much, India can do a lot more. Economic sanctions are the first on the table: as the South Asian superpower, India can impose harsh economic and cultural sanctions on Pakistan. India can also press for hard sanctions from the IMF and the World Bank (though a UNSC sanction would be impossible).
Diplomatic pressure is also a potent weapon. India has most of the world on its side. It must make it very clear that while India is not blaming the civilian Government in Islamabad for 26/11 (though it is blaming the military and the ISI), that does not absolve the civilian government of any responsibility. Every state has to act against non-state actors coming from their soil. Pakistan must be forced to stop using terrorism as an instrument in the Kashmir issue.
A few days before Afghan President Hamid Karzai's visit to India, an Afghan official said that in the past, Pakistan had been given proof by Afghanistan of terrorists using Pakistani soil, but Pakistan readily denied it and nothing moved ahead. Afghanistan could not do much, but India can. And India must.