Lionel Messi has never been transferred in his professional career - but if he was, how much would he cost?
That hypothetical question is sure to be have been debated in pubs and bars, student digs and family sitting rooms across the country, as the little Argentinian has established himself as the world's best player.
His chief rival for the mythical title of world's greatest - Cristiano Ronaldo - moved in 2009 from Manchester United to Real Madrid for £80m - a world record fee.
But since then the Portuguese star has got even better, bagging 101 La Liga goals in just 88 appearances, and his value has surely only increased in the preceding three years.
At 27 years old, Ronaldo is in the prime of his career, and Real Madrid, in a strong position financially, are well-placed to extract maximum value should he be sold.
But, if Ronaldo's performances have been astounding these past three years, and his value has increased from an eye-watering £80m, what adjective can possibly describe the achievements of Lionel Messi?
The Barcelona forward is a three-time Ballon d'Or winner, capable of scoring 82 goals across a season - a individual stats sheet even Ronaldo cannot match.
So how much to buy this talent? Manchester City, Paris St Germain and other clubs with similarly healthy overdrafts have surely asked the question, surely discussed a figure, if only in hope rather than expectation.
A recent GMF poll asked football fans how much they think the 25-year-old would be sold for, if Barcelona could ever be tempted.
From more than 25,000 votes, almost two-fifths of fans believe the Barcelona superstar is worth between £100m and £125m.
That valuation corresponds with the work of transfermarkt.co.uk, who state the current market value of Messi is somewhere around £105m. As a way of comparison, Ronaldo is valued on £88m by the transfer market experts, Wayne Rooney at £57m and Andres Iniesta at £61.5m.
But some fans think he's worth much more, with 30% of supporters valuing Messi at no less than £200m.
Robbie Savage, former-Premier League footballer turned BBC pundit believes he's worth at least £150m. The exact figures may differ slightly, but it's without doubt that the Barca star is worth more on the transfer market than anyone else in history.
In today's commercialised game, a player's value transcends the football pitch - such decisions to spend £80m on one player are as much about selling shirts as winning trophies.
And suc fees would shatter the current world record, taking football into unchartered territory.
Messi would be worth more than most teams. One player as valuable as entire clubs. Worth more than Zinedine Zidane, Luis Figo and Ronaldinho at the prime of their careers combined.
Football seems to run well ahead of inflation anyway, but transfer fees are a different beast altogether.
The unstoppable rise has been steady and constant, as new wealth pumped into the game has inflated transfer fees to previously record levels.
Between 1979 and 1995 the British record fee increased by just under £7m. The subsequent 6 years saw it jump from £8.5m for Stan Collymore in 1995 to £28.1m for Juan Sebastian Veron in 2001.
In 2009, Ronaldo's move almost trebled the British record - turning it into a world record. A move for Messi would likely double that again.
But Barcelona are unlikely to ever sell, why would they, and while you can never say never, Messi has reiterated his desire on several occasions to stay at Barca for the majority of his career, before possibly returning to Argentina.
Manchester City, Paris St Germain and Chelsea can dream, but unless something goes catastrophically wrong at the Nou Camp, Messi is likely to stay put.
How much do you think Lionel Messi is worth on the current transfer market? Join the debate by leaving a comment below...