Both science and law rely on evidence and yet they use the same word in subtly different ways. For a scientist to state that "there is no evidence" doesn't necessarily mean that no evidence was presented, but rather that it was thought to be unconvincing.
The judges presiding over the case may well take the view that if that is the way scientists wish to speak then "scientific evidence" will be deemed to be a statement of opinion rather than of fact. Simon Singh's comments would be considered "fair opinion", as would any subsequent expert scientific testimony. This would also free up scientific debate without the sword of libel hanging over every statement; a claimant would then have to prove malicious intent.
But, would scientists be happy being considered pundits rather than experts?