Ok, I'm not particularly great at understanding trains and timetables and stuff anyway, and I'm getting really confused on the London Underground website, so I thought I'd ask here.

I will be in Brixton on Tuesday evening, and I'd like to know the latest train I can catch from there so that I can make it back to Amersham station that same night. Because if I don't get that train, I could get stuck in London until the morning.

Thanks in advance.

Brixton on victoria line at 23.37, at Kings Cross take metropolitan line to Amersham getting in at 00.52