It is a racing certainty. The tilting trains have meant this didn't need to be grasped until now. It was probably the right solution all along, but 140mph needed tilt and that had been specified before the downgrade. It wouldn't surprise me completely to see only two speed categories. Mind you upthread a member said what a good ride you got with tilt on the northern WCML and they are absolutely right.
It was definitely tilting trains proposed for a 125mph speed profile under the ‘PUG1’ proposals, the principles of which were agreed in June 1996. I have a copy somewhere. It was only when Virgin rocked up with ‘PUG2’ 6 months later did 140mph come to the party, but the principle of tilt preceded it.