The search is now on to find the owner of the winning ticket, bought in West Lothian, who matched the five main numbers and one Lucky Star number in the EuroMillions draw on December 11, 2020.
The winning EuroMillions numbers on that date were 6, 9, 13, 24, 41 and the Lucky Star numbers were 3 and 12.
The lucky ticket-holder has until June 9, 2021 to claim their prize.
The £1.8M prize was the result of the EuroMillions pre-Christmas roll series, which saw the jackpot reach record-breaking levels.
In the draw on December 11, the jackpot was won by a French ticket-holder and a total of five lucky UK players picked up £1.8 million each just by matching the five main numbers and one Lucky Star number.
Anyone not in possession of their ticket, for whatever reason, can still make a claim in writing to Camelot if they believe they are the lucky person, but it must be within 30 days of the draw.
Camelot’s Andy Carter, Senior Winners’ Adviser at The National Lottery, said: “We’re desperate to find this mystery ticket-holder and unite them with their winnings, this amazing prize could really make a massive difference to somebody’s life, and what a way to start the New Year it would be.
"We’re urging everyone who bought a ticket in this area to check their old EuroMillions tickets again or look anywhere a missing ticket could be hiding.”