Aside from the Europe-wide middle finger
In Britain the V-sign (index and middle finger raised) has essentially the same meaning as the middle finger, but only if your palm is facing inwards. It's easy to muddle this with the peace sign (palm facing out) which has led to a few funny misunderstandings over the years. The 'wanker' sign (loose fist shaken slowly side-to-side) would doubtless be understood everywhere but I've only ever seen it here and mostly at football matches