Found in a mixed box of bits from an old shed on the Anderton boot sale recently.
PIFCO Fuse Wire.
1. Turn off main switch
2. Pul out fuses in turn until the one with broken wire is located.
3. Remove old wire and wipe porcelain clean.
4. Insert a new length of wire of the correct type.
5. Replace fuse, close box and turn on main switch.
Made in England