Does the covering look like Hessian on the brown cables? It looks like
Poly Butyl Jute (PBJ) cable and will probably be end of life. Do not
tamper with it but call the local electricity supplier (the old
electricity board for the area) and state that you may have a PBJ supply
* cable and you would like it checked. If they do replace it it will be
for free.

Cable is brown rubber. Most of it has ben painted over but brown bits
look sound. Its the cable clips that have deteriorated.