I have found
this source for kevlar cord. It costs 40p and is 1.5mm thick. The test strength of this cord isn't listed on the site. I have done some searching for the strength of kelvar cord and found the following: Kevlar cord 1mm thick - 100kg (220lb). The thicker cord must be stronger than that. This seems like it could be quite a good contender for a survival kit cord. However I don't know anything about the flexibility of the cord. It could be like wire, I don't know. It comes in four colours too: White, black, purple and pink <img src="images/graemlins/grin.gif" alt="" />.