London (CNN) -- Six months ago, a winning ticket was bought for the Euromillions lottery draw in or near the English town of Stevenage, north of London. But the jackpot -- a sizable £63.8 million ($103 million) -- has never been claimed.
And whoever holds the golden ticket has only until 11 p.m. (6 p.m. ET) Wednesday to claim their prize, or the whole sum will go to charity.
The search for the unknown winner has gripped the centuries-old town of 84,000, as well as the smaller neighboring town of Hitchin.
Euromillions, which said the ticket was bought in the Stevenage and Hitchin area, has made repeated appeals to try to find the missing ticket-holder. A billboard campaign has even been run in a central square in Hitchin, an old market town.
Whoever it was matched all five numbers, 5, 11, 22, 34 and 40, and the Lucky Star numbers -- 9 and 11 -- in the Friday, June 8, draw.
A Euromillions press statement attempts to jog the memory of the ticket holder, who it suggests may have come from the area or stopped off while driving through.
"Britain was gripped by Olympics fever, with the Games just seven weeks away, and the Queen's birthday celebrations had seen the Royal Flotilla on the River Thames just the weekend before," it says.
CNN's Richard Allen Greene and Laura Smith-Spark contributed to this report.