The £1m Bank of England note is dated 30 August 1948
A £1m Treasury note has fetched £78,300, twice the expected price, at an auction in London.
The note, numbered 000008, was issued after World War II in connection with the Marshall Aid Plan.
The Marshall plan was a programme of funding given to Western Europe by the United States to help with recovery after the war.
Another £1,000,000 note numbered 000007 was sold for £8,000 in 1977, through a private sale.
It was listed by the Guinness Book of Records as being the highest denomination in private ownership.
The number eight note is dated 30 August 1948.
It bears the signature of E E Bridges, secretary to the treasury, in the lower right hand corner and is cancelled over the signature and stamped 6 October 1948, Bank of England.
Before the sale a spokesman for Spink auction house told Coinlink that the defunct number eight note, entered for sale by UK-based banknote collector Bill Parkinson, was expected to fetch between £35,000 and £40,000 in the world banknotes sale at its auction house in Bloomsbury.
It is believed notes number seven and eight are the only remaining notes of nine that were produced at the time.
They were given as mementoes to the US and UK Treasury Secretaries.