Boiled Beef and Triffids

I am currently reading John Wyndham's Day of the Triffids, and lovin' it.

But I've come to an impasse.

On page 42 of the Penguin paperback, the second full paragraph, on the subject of the triffid, starts thus:-

But there were features of it to be less casually dismissed. On its origins the Russians, true to type, lay low and said nuffin.

"Nuffin"?

Is this...

a) The narrator showing the first signs of the disease now known as "mockney"?

b) Wyndham slipping in a rogue working class word to make sure that we, the reader, are awake?

c) A sly dig at the elocution skills of the proletariat?



I can't go on unless I know which.