I forgot I bought these the other day, just after I got the Mk28 I think...
http://www.ebay.co.uk/itm/390492035742http://www.ebay.co.uk/itm/271097313701Anyway, got them mostly cos they were there, but mainly cos I wanted something a bit different for the Mk28, and the ivory one just cos I could...

I don't really know much about these, just that they have a Plug No. 420 on one end and the usual spades & grommet on the other, and they need a Jack No. 95A or 95B to connect to...

I think they were used as part of Extension Plan No. 4, which was essentially what we have today, just wired slightly differently and always had a bellset connected to the line, so you could have a few points round the house or business to which you could connect your phone to without having to have it re-wired by a GPO engineer...
But anyway, pictures, thought I'd do a size comparison of the 420s against a US 283B plug, a BT Plug 431, and an RJ11, and you can see the 420 is HUUUUGE in comparison to all three, I can understand why they dropped those in favour of the 431...
