They were intended for internal use as "records of movement" and were in use for only a period of six weeks.
THE Marshall Plan formed the backbone of the European recovery process following the Second World War. The aid programme ran into billions of dollars over several years and was set up to help rebuild the shattered countries of the continent. Its thinking was first set out by the then US Secretary of State, George C. Marshall, speaking at Harvard late in 1947.
But it wasn't just the Americans who became involved as benefactors - the Allies rallied round en masse, including Britain.
Unlike the usual banknotes, which carry a promise from the Bank of England to pay the bearer on demand the sum shown, this Treasury Note states that it "entitles the Bank of England to payment of one million pounds out of the Consolidation Fund of the United Kingdom".
The note is hole-cancelled over the signature and stamped Cancelled, 6 October 1948, Bank of England.
The two surviving examples, numbers seven and eight, were given as mementos to the respective US and UK Treasury Secretaries. In the UK's case this was E.E. Bridges, whose printed signature appears on the note, bottom left.
Number seven was first sold in 1977 and is listed in the Guinness Book of Records as being the highest denomination note in private hands.
As ATG coins specialist Richard Falkiner recalls, number eight - the note on offer at Spink on October 1 - from the Bill Parkinson collection - previously sold at Christie's on October 9, 1990, where it took £21,000 against a £20,000-30,000 estimate.
Spink have hopes of around £40,000 for it this time.
By Ivan Macquisten