In international football, few rivalries are greater and none are older.
According to former Scotland coach Craig Levein, Scotland vs. England is 'the ultimate contest. It really is as good as it gets.'
But so fierce is the rancor, that a quarter of a century ago, facing a losing battle against rampant hooliganism, their annual matches had to be abandoned.
There will be lots of insults flying across the way, but it will all be done in a reasonably good spirit
Now, for the first time since 1989, the old foes are meeting again at their choosing despite sporadic fan violence returning to haunt football in recent years and presenting security fears ahead of Wednesday's game.
A heavy police operation is in place across London as Wembley Stadium prepares to host the 111th meeting between the cross-border rival since the first in 1872.
The English Football Association said a considerable amount of 'intelligence-led work' has been undertaken with the police prepared for an influx of fans from north of the border.
Police Scotland has sent specialised hooligan spotters to London to work alongside the London force, with officers particularly wary of fans amassing in the capital's main square and drinking through the day.
"We are aware that traditionally Scotland supporters congregate in Trafalgar Square and this will form part of our policing operation,'' the Metropolitan Police said in a statement, describing their plan as 'appropriate and proportionate.'
It will be a friendly in name, but not necessarily in nature.
"There will be lots of banter,'' England coach Roy Hodgson said.
"There will be lots of insults flying across the way, but it will all be done in a reasonably good spirit."
'Trust the fans'
The only England-Scotland games since 1989 have been in official competitions, with the neighbours facing off at the 1996 European Championship in London, and home and away three years later in a Euro 2000 playoff.
In May, fears of violence proved unfounded when England played Ireland for the first time since disorder forced their last fixture in 1995 to be abandoned, raising hopes that Wednesday's game will also pass off peacefully.
But in 2011 when England hosted another neighbour, Wales, a visiting supporter was killed in an attack outside Wembley by an England fan, who was later jailed for three years.
"I trust the fans," Hodgson said.
"I think the behaviour of fans has improved enormously. We did have a little period many years ago when fan behavior was a problem, but an awful lot has been done and fans are more responsible."
Hodgson, though, is old enough to remember when football grounds were a different, less welcoming, environment.
As is Scotland coach Gordon Strachan. He was at Wembley on his honeymoon in 1977 when, after a memorable 2-1 victory, Scotland fans poured onto the pitch, ripping up pieces of turf to take home and tearing down the goals.
However, a peaceful Euro '96 game, which England won 2-0, offered hope the rivalry could be resumed with regular meetings.
But three years later, there were running battles between fans in Glasgow around the first leg of their Euro 2000 playoff, leading to more than 200 arrests. England won 2-0 at Hampden Park and qualified despite losing 1-0 on home soil.
It's only the FA's 150th anniversary that has brought the rivals back together on a football pitch amid a congested fixture calendar where England seeks more competitive and lucrative games.
Adding to intrigue is the possibility that by the next time the teams meet, the 'Auld Enemy' could have broken away from Britain.
(It) is the most important international game I have played in and I will imagine it will be on a par with anything I have played in club
A referendum in September 2014 will determine whether Scotland ends more than 300 years of political union with its more populous southern neighbour.
Though the two countries have shared a government since 1707, centuries-old tales of English brutality and Scottish resistance still have strong emotional resonance, with Scottish schoolchildren taught about victories over invading armies from the south.
In football, though, the countries have rarely been a force despite helping to invent the game and playing the first international match - a 0-0 draw in 1872.
England, who recently dropped to 14th in the FIFA rankings, have won the World Cup just once in 1966. Scotland, at 50th in the FIFA rankings, have never won a major tournament and have not qualified for the World Cup since 1998.
Scotland striker Shaun Maloney acknowledges there is now a 'decent margin between us and England.'
Accepting Scotland's lowly status, playing - let alone beating - England is a career-high for Maloney.
"(It) is the most important international game I have played in and I will imagine it will be on a par with anything I have played in club football,'' said Maloney, who won the FA Cup with Wigan at Wembley in May.
"I understand it is a friendly and some of their players will play 45 minutes, but for us it will mean the world."