Hmmm.
Have got tubes and kit to replace/repair the dreaded 'P'.
Got multi tool that comes with new bike with Wiggle.
Not thought about chain problems.
What else do you think I should be carrying with me??
Cable ties & duck tape (in case anything comes loose).
If you have mudguards, some spare mudguard bolts.
A spare folding tyre, just in case you get the dreaded recurring puncture.