My short ride 'essentials' checklist would be:
- Tyre levers, patches, mini hand pump (and no, a mini hand pump will not get you much past 80, it's a stop-gap measure) and a multi-tool (allen keys). So I can fix most things and get home fine.
- Phone, £10, Oyster card, debit card. So if I can't fix it, I have options.
For a longer ride I would take a spare tube and a C02 cannister, some snacks, a water bottle (or two), and think more carefully about clothing