Organisers have said they are expecting a ticket sales frenzy ahead of the £113 million EuroMillions jackpot draw.
A single ticket winner would break the British lottery record, the National Lottery said.
The busiest time for ticket buying is expected to be 5.23pm, when sales are anticipated to be more than 122% higher than at the peak time during a normal week.
A National Lottery spokesman said: "This week's jackpot is a record-breaker and we know that Brits grab that Friday feeling on their way home from work by ensuring they are in with a chance for the giant jackpot.
"Preparations for the winner include staff who can all move to support the winner in an instant - it is a major undertaking. The EuroMillions rush means more money raised for Good Causes all over the UK, adding to the £24 billion raised to date."
The current overall EuroMillions record win is £113,229,891 banked by a single ticket-holder from Spain in the draw on May 8 last year.
The current biggest British EuroMillions win is held by Les and Sam Scadding, from South Wales, and the Magnificent Seven syndicate from Liverpool, who each won £45.5 million on November 6 last year.
The jackpot is just below breaking the European record set by a single ticket on the Italian SuperEnalotto game which banked £128.3 million (147.8 euros) on August 22 last year.
If no-one matches all five main numbers and the two Lucky Star numbers, the jackpot will roll over to next Friday's draw.
Nine countries currently play EuroMillions. They are the UK, France, Spain, Austria, Belgium, Luxembourg, Ireland, Portugal and Switzerland.
