The National Lottery is on the hunt for 12 missing millionaires after 100 winners were drawn from a single EuroMillions draw.
So far 88 winners have come forward and claimed their prize but two weeks after the draw, which took place on 26 July, there are still 12 who have yet to bank their £1 million winnings.
If all 100 people do come forward it would be a new world record, which was set last year when 97 millionaires were made in one draw on the night of the Olympics opening ceremony.
A National Lottery spokesman said: "Imagine walking around not knowing you are a millionaire. We urge every player to check their tickets as there are life changing prizes waiting to be claimed.
"The clock is now ticking for these ticket-holders and we want to get the prize into their bank account so they can start enjoying their win as soon as possible.
"Check in the bottom of your handbag and in every coat pocket, even have a rummage down the back of your sofa - the ticket could be lurking anywhere.
"This draw has been life changing for 88 ticket holders already and we are desperate to find our missing millionaires. This special draw, like every draw, helps to raise more than £35 million every week for National Lottery Good Causes across the UK."
The missing prize winners from the EuroMillions Millionaire Raffle draw will have until January next year to claim the money.
The areas where the missing tickets were bought are: Fife, County Borough of Rhondda Cynon Taf, Bristol, Blackpool & Borough of Fylde, Kensington & Chelsea, East Dunbartonshire, West Dorset and Weymouth and Portland, Gloucester, Bolton, Brighton and Hove and the London boroughs of Havering and Sutton.