This is the report they reference, the 7 year old "latest" evidence from the independent Advisory Council on the Misuse of Drugs, which quite clearly in it's introduction states:
"Criminal justice measures – irrespective of classification – will have only a limited effect on usage. We therefore urge you to invite the UK’s Chief Medical Officers to develop, on behalf of the government, a public health strategy that will meet our shared goals. Anything less will prejudice the health of future generations."
Guess they didn't even bother to read that far, and it's on the first ...king page! And then we have to consider that they actually sacked Professor David Nutt the following year, in 2009 for daring to suggest that alcohol and tobacco are more harmful than LSD, ecstasy and cannabis. So it's only evidence if it agrees with their blinkered stance, and we can all go to hell for imagining otherwise. What has happened in the 7 years since this was said? Cannabis was instead upgraded from Class C to Class B... Harsher prison sentences, well done!
I'm genuinely sickened by this, and the absolute lack of respect the UK government is showing it's citizens. I do feel the scope of the petition was too great, the UK government would be very unlikely to make the jump to 100% legal immediately, however for there to not even be a debate is ridiculous.