6mm flat twin NO earth?

There certainly were twin without earth cables in the old days - but more usually seen in smaller sizes - typically on lighting circuits - where earthing to all-insulated or out-of-reach accessories wasn't considered necessary. The other possibility is a T&E cable that has had the c.p.c. neatly cut back.

For the likes of a cooker, it was likely that earthing would have been needed from the outset - but that may well have been provided by separate earth conductor (often bare) alongside the twin cable, or even just to a local water pipe.

I'd have to lookup the imperial equivalent of 2.5mm² T&E - I've a feeling the 7-strand L&N were slightly larger than 2.5mm² but the 3-strand c.p.c. was a little smaller than 1.5mm². I've a vague recollection that early metric (solid core) 2.5s had a 1.0mm² c.p.c. (which often doesn't meet modern adiabatic requirements).

   - Andy.

There certainly were twin without earth cables in the old days - but more usually seen in smaller sizes - typically on lighting circuits - where earthing to all-insulated or out-of-reach accessories wasn't considered necessary. The other possibility is a T&E cable that has had the c.p.c. neatly cut back.

For the likes of a cooker, it was likely that earthing would have been needed from the outset - but that may well have been provided by separate earth conductor (often bare) alongside the twin cable, or even just to a local water pipe.

I'd have to lookup the imperial equivalent of 2.5mm² T&E - I've a feeling the 7-strand L&N were slightly larger than 2.5mm² but the 3-strand c.p.c. was a little smaller than 1.5mm². I've a vague recollection that early metric (solid core) 2.5s had a 1.0mm² c.p.c. (which often doesn't meet modern adiabatic requirements).

   - Andy.

Yes the lighting circuits for this property have no earth but I can explain that.

When I looked at the cooker cable my first thought was that it was cut or broken out of sight however after investigation there is no CPC at the CU end. The cooker circuit has been extended and must have a join somewhere, the switch/socket has a CPC but I dont know where it is conncected too!