Yup, the only way this begins to hurt for the Tories is if someone on the opposition benches (I don't care if it's Labour, SNP, Lib Dems, or Greens) steps forward and can take the live ammunition Cummings is handing over and actually make use of it in a way that will get the general public to re-assess. Cummings is playing a very clever game by waiting until Hancock gave his evidence and then shooting for the low-hanging fruit in providing evidence of untruthfulness, but he's forgotten that he simply cannot win the game in the court of public opinion because he's already lost that war a long time ago.
It's a right shame that there's no one with the magnetic personality that average Jo(e) just loves and trusts by instinct to oppose the Tories. Starmer's a decent leader for Labour if they want to tread water at a higher level than Corbyn (who was struggling to keep head above water in the end), but he's not going to get them back on dry land based on what's happened so far. Even with the Tories apparently quite happy to provide the ammunition that should bring them down.
I agree with all that but match day isn't for another 3 years. General elections are won in the weeks in the run up, and most of all, on the day we vote. Apparently the little bald yorkshireman whose name now escapes me (which is telling) used to duff up Tony Blair at the dispatch box twice weekly, but when it came to general elections it was another matter.
If in 3 years we are in a pickle then labour has a chance. If we are in sunny uplands then Boris will get another term, provided Gove hasn't stabbed him in the back in the meantime.