This fine and wearable necklace is from the Naga people, and most probably the Konyak Naga.
It has been strung with orange, red, white and blue glass trade beads, small cast brass bells, and black wood (or possibly blackened bone) spacers.
The beads have been strung on native cotton twine. The catch comprises a simple twine loop and a metal disc.
Interestingly, the bead layout is asymmetric, making this example more visually interesting than most.
Similar examples are illustrated in Jacobs (1990, p. 320).
The necklace is in excellent, stable condition, and has clear and obvious age. Almost certainly, it has been in the UK since colonial times.
Jacobs, J., The Nagas: Hill Peoples of Northeast India, Thames & Hudson, 1990.