As the clocks on the two giant screens at either end of the giant bowl continue the countdown towards the final whistle this trickle invariably turns into a stream and then, finally, a flood the moment the fourth official holds the board aloft to indicate how many minutes of stoppage-time will be played.
Such is the desire to get away and beat the queues into the three nearby tube stations that almost as many fans can be found outside Wembley as inside when the referee finally calls a halt.
Yesterday, however, was different. Those same clocks ticked past 75 minutes, then 80 minutes and 85 minutes, and you suspected not one of the 78,221 fans who had opted to spend their Sunday watching the final act of the UEFA Nations League A Group 4 played out moved an inch. Or, if they did, it was to edge fractionally further forward in their seats.
A few did finally began to stir when fourth official Damianos Efthimiadis indicated there would be a minimum three minutes of stoppage-time. Even then, though, those heading for the exits got as far as the last step before turning back one last time to check they were not missing any late drama.
If ever there was a ringing endorsement for this new competition then this surely was it. Introduced by UEFA as an antidote to a schedule that had become long on meaningless friendlies and short on genuine competitive football between the bi-annual major tournaments, the Nations League has already delivered.
Sure, the format of three-team groups in Leagues A and B mean this is surely as ruthless a competition as elite sport has seen. One wrong move and a team can go from favourites to finish top to being relegated.
But this unpredictability is part of the fun. And, boy, was yesterday afternoon a fun day for those who have waited a long time for the Three Lions to roar again.
It started early with there being a definite sense of occasion in the air as fans making their way to Wembley debated the various possible outcomes come 4pm.
A win for either of the two combatants meant a place in next June’s semi-finals. Lose, meanwhile, and relegation was confirmed. A draw and Spain would qualify, leaving Croatia dropping through the trapdoor if the score ended goalless or England if goals were involved.
Once Andrej Kramaric had put the visitors in front Gareth Southgate’s men needed two goals not just to win the group but also avoid the drop. It made for wonderfully exciting fare and, for all but the 2,200 noisy Croatians housed in one corner of Wembley, a deliriously happy ending.
Portugal now awaits the Three Lions next summer for a four-team tournament featuring the hosts, Switzerland – after their amazing win over Belgium – and either Holland or France.
The draw for the semi-finals will take place on December 3, 24 hours after the group stages for Euro 2020 qualifying are drawn.
Porto’s Estádio do Dragão and the Estádio D Afonso Henriques in Guimaraes will host all four games, including a third-place play-off, between June 5 and 9.
The Nations League has been compared in some circles to the League Cup in this country: hardly a competition whose capture represents the pinnacle of anyone’s ambition, but a decent place to start for any team with genuine aspirations of landing the bigger prizes later on.
Norman Hunter, the former defender who was at Wembley yesterday, knows better than most just what a useful springboard to greatness lifting the League Cup can provide.
Don Revie’s Leeds beat Arsenal in the final at Wembley 50 years ago to secure the club’s first major trophy. A little over a year later the first of two league titles had been secured by a team who dominated English football for the next six or seven years.
Only time will tell if success in Portugal can propel England on to the bigger prizes in time, but for a side clearly blossoming under Southgate next summer could be huge.