The rare comic book is up for sale on Ebay. An auction in 2011 saw Nicholas Cage's copy of the iconic comic sell for $2.1 million.

The auction began on August 14 with a starting bid of $1.7m, 27 bids have been made reaching a sum of $1.950.100. The auction closes on August 24 the price may still soar.

Seller Darren Adams said of the comic book: "It is referred to as the Holy Grail of comics and this is the finest graded copy to exist with perfect white pages. This is .... the Mona Lisa of comics and stands alone as the most valuable comic book ever printed."

Proceeds from the sale of the 1938 comic will go to the Christopher & Dana Reeve Foundation.

See more comics on Barnebys here.