What maximum amperage for cables

[clez50]

This question has probably been asked several time but things change. The house I'm living in now was built in the 1960's and has a ring main using 4mm Flat Twin and Earth. A lot of properties I've noticed have been wired with 2.5mm FTE and both connected through originally a 30amp fuse or more lately a 32amp mcb. My question is what's the maximum amperage that each size of cable can carry?

 

[davesparks]

He says it's copper coloured, so that suggests metric, in which case it wasn't made in the sixties.

Suggests yes, but doesn't prove it, not all imperial cables were tinned.