The missing link here is nobody is saying what the "new conditions" were that ended the negotiations late on Tuesday. Jim Spence might know but does not have permission to reveal them. Despite what he says Tommy will know along with Brown, May and Vine.
One obvious possibility for the silence is that there is indeed a chance that the deal can be brought back to life. May's side are keeping quiet in case a so called better deal from elsewhere proves a disappointment. Brown, who is surely an experience negotiator, will know that May was keen enough to sign and so will stick to his guns.