No one has come forward to claim the record-breaking 113m EuroMillions prize following the draw on October 8.
The ticket-holder could immediately become the 589th wealthiest person in Britain, according to the Sunday Times Rich List 2010.
To speed the process up, Camelot will announce on Friday in which region the ticket was bought.
Until the draw, the largest lottery winner in the UK was an anonymous player who scooped 84.4m on the EuroMillions draw in May.
The latest winner who picked the winning numbers 9, 30, 35, 39, 46, with lucky stars 6 and 8, defied odds of 76,275,360 to one to guess all seven numbers correctly, or placed their faith in a lucky dip.
They have 180 days from the draw to make a claim with a valid ticket, meaning this prize can be claimed up until 5.30pm on April 6 next year.