A mystery lottery player has lost out on a £64 million fortune after the deadline for them to claim the life-changing prize expired.
The unlucky individual, who bought the winning EuroMillions ticket in Hertfordshire, had until 11pm yesterday to collect the massive windfall.
But despite a National Lottery publicity campaign, the would-be multi-millionaire missed the 180-day deadline - making the £63,837,543.60 prize the biggest unclaimed lottery win in history.
The bumper haul of money, plus all the interest it has generated, will now go to the National Lottery Good Causes - adding to the £29 billion already raised through sales of lottery tickets since the National Lottery launched in November 1994.
A National Lottery spokeswoman said: "Unfortunately, I can confirm that the ticketholder did not come forward within the deadline to claim their prize and has now sadly missed out on this staggering amount of money.
"The vast majority of prizes are claimed within the 180 days but to avoid this unfortunate situation happening again, we would urge all National Lottery players to check their tickets on a regular basis."
The now-expired ticket was purchased in the Stevenage and Hitchin area for the EuroMillions draw on Friday June 8.
National Lottery officials launched a desperate search for the holder, raising awareness through adverts and posters - with even a town crier proclaiming the win from a Lamborghini.
All lottery players were urged to check their tickets and search some of the more unusual places where "lost" tickets have been found in the past, such as in bin bags, wedged down the back of sofas and stashed in car sun visors.
The lottery spokeswoman added: "We tried very hard to find the ticket-holder, with lots of awareness-raising activity over the past 180 days, and it's a real shame that they have missed out, but there is still one winner - the nation.
"This money, and all the interest earned over the 180 days, will now go to the National Lottery Good Causes - adding to the £29 billion already raised and distributed to over 390,000 individual awards that have benefited people, communities and projects across the UK."
The missing ticket-holder matched all five numbers - 5, 11, 22, 34 and 40 - and both Lucky Star numbers - 9 and 11.
Before last night, the biggest unclaimed lottery win was £9.4 million after the owner of a lucky ticket bought in Doncaster in July 2005 failed to come forward.