Does anybody know what this is? I got a packet of mixed climbing annuals, but it doesn't specify what is in there.
A Morning Glory perhaps?
I think it's Morning Glory (Ipomoea purpurea).
Thunbergia leaves are coarser-looking and have a slightly toothed edge, in my experience.
Looks like Morning Glory to me too.
Thanks everyone, it's certainly growing fast - I put it on the little table next to me when I had my tea (don't know why really, I just like to have my plants nearby ), and by bedtime it had grown past its cane! Will come in handy for screening next door's shed, at least temporarily.