This is disingenuous to the point of being dishonest. Reference:

Williams: “You I think, Richard, believe you have a disproof of god.”

Dawkins: No, I don’t! you were wrong when you said that. I constructed in The God Delusion a 7-point scale, of which ’1′ was, ‘I know god exists’, ’7′ was ‘I know god doesn’t exist’ and I called myself a ’6′.

[...]

Dawkins: “I believe that when you talk about agnosticism, It’s very important to make a distinction between ‘I don’t know whether X is true or not, therefore it’s 50-50 likely or unlikely’ and that’s the kind of agnostic which I don’t-which I’m definitely not. I think one can place estimates of probability on these things and I think the probability of any supernatural creator existing is very very low. So I’m-let’s say I’m a 6.9.

..

On pp50-1 of The God Delusion, Dawkins lays out the 7 point scale he referred to in this conversation. Here are points 6 and 7 of the 7-point scale:

\6. Very low probability [of the existence of god] but short of zero. De facto atheist: ‘I cannot know for certain, but I think god is very improbable, and live my life on the assumption that he is not there.

\7. Strong atheist. ‘I know there is no God, with the same conviction as Jung “knows” there is one.

Dawkins goes on to say:

I count myself in category 6, but leaning toward 7 – I am agnostic only to the extent that I am agnostic about fairies at the bottom of the garden.