That's the worst interview performance by a senior British politician that I've ever heard (and I'm a member of the Labour party and an ex-civil servant, so god knows I've heard some bad political interviews in my time).
Two really worrying things about it for anyone who thinks that a functional opposition is essential in a parliamentary democracy. First, one of Labour's most senior politicians seems either to have lost the ability to think on her feet or become so complacent inside the Cobynite bubble that she doesn't care if she sounds like the hungover student who turned up to class and suddenly realised they were supposed to be doing that week's presentation. Any even half competent politician could have made a better effort at getting hold of the interview than she did. She used to be very sharp, so something's gone badly wrong.
Second, and more worrying, is that she obviously wasn't properly briefed. She should have had all the figures in front of her from the start, clearly marked up, with speaking notes. The fact that it took a good 5 minutes before someone stuck the figures in front of her suggests there's no infrastructure of competent advisors and other back office people of the kind that parties need to function. This is the most basic requirement of politics - if you don't have people doing this then you don't have a party that has the organisation and competence to operate even as an oppostion party, let alone a governing one.
I'm a Labour member in a Labour/Lib Dem marginal and until this I was still planning, despite everything, to vote Labour. I'm not sure I can now.