This strategy is, obviously, not without risk. If Cameron had dried up on stage or mangled something beyond repair then the crisis story would have been escalated. The intensity with which George Osborne and Michael Gove, Cameron’s two closest shadow Cabinet allies, were listening to the speech showed how much was at stake.
The Labour critique of the speecg is that it lacked ‘substance’. This rather suggests that they don’t see any obvious weaknesses in it.