On July 30, 1966, Wengrow was at Wembley for the World Cup final between England and West Germany.
He was there as a guest of the Football Association, through his friendship with Vincent Wright, the stepson of England legend and former Arsenal manager Billy Wright.
And, naturally, Martin Wengrow has a story about how he ended up there.
"I jibbed into that game at Wembley. I had jibbed into a couple of the qualifiers previously. England played France, for example," Martin recalled to Football Presse.
"But a very good friend of mine, still a good friend today, was Vincent Wright. He's the stepson of Billy Wright, who was a very famous England footballer with 105 caps and later became manager of Arsenal.
"Not long after Billy Wright got sacked by Arsenal, the FA had employed him as a coach. Vince's mother was Joy Beverley, one of the Beverley Sisters, who were enormously famous at the time. Billy Wright had married Joy, and the three sisters were big celebrities. They were a bit like Posh and Becks of today, although obviously you didn't have the same level of scrutiny."
That friendship changed the way Wengrow experienced the biggest football match the country had ever staged.
"I was invited to the World Cup by the FA, really. The FA had employed Billy Wright as a coach before he got the Arsenal job, and that was actually his only experience of coaching, which was ridiculous really, coaching youngsters and then getting the Arsenal job.
"But because of Vince, I was picked up from my home by a very big black limousine which was laid on by the FA and the Beverley Sisters. They always used to dress in identical clothes, just to make it difficult to recognise them.
"So that was it really. I went as a guest of the FA. I didn't have to jib into the game, I went in nicely, and there was an after-pass to go into the media place afterwards."
Wembley was packed for a final that would become one of the defining moments in English sporting history. England fell behind to Helmut Haller, levelled through Geoff Hurst and then took the lead through Martin Peters. Wolfgang Weber's late equaliser sent the final into extra time before Hurst scored twice more to complete the first hat-trick in a World Cup final. England won 4-2.
For Wengrow, though, there was an important distinction between witnessing England's greatest football achievement and his own relationship with the game.
"I'm not a big England supporter. I want England to win, but I don't mind if they lose either.
"All my passion for football revolves around Arsenal Football Club. So if England win the World Cup, which they came upon occasionally when they went and played in these tournaments, fine. But if they lose it, it's not a disaster for me."
Yet even for an Arsenal obsessive, this was impossible to regard as an ordinary afternoon.
"Yeah, so that was a great day. It was the day that I took my wife out for the first time as well, coincidentally, that evening.
"After going out for a meal with another couple, we went and joined the celebrations in London for the World Cup in Kensington, where the team was staying.
"It was a very memorable day."
There was an extraordinary personal symmetry to it. Wengrow had spent his youth developing an obsession with Arsenal and football, but the woman he would marry was entering his life on the same day England lifted the World Cup.
They would eventually spend 56 years together.
"I've been married 56 years, and she understood this passion of mine and she let me get on with it.
"She didn't really put any obstacles in the way right the way through. I was very unfair, I wasn't a good father, I wasn't a good husband. I had to be at every Arsenal game, even when my kids were babies and little boys, until one of them started coming and the other one didn't take to it.
"So without her I couldn't have indulged in this passion.
"But to be fair, I did tell her before we got married, 'This is who I am, this is what I do, this is what I love, and if you're going to marry me, you have to accept part of my life.'
"She's done it with gratitude, so I've been a very lucky fellow in that respect."
For all the extraordinary circumstances surrounding his day at Wembley, Wengrow's memory of 1966 isn't simply about being present when England became world champions.
It is about what it represented at the time.
Football was different. Wembley was different. The FA Cup and international football dominated the national sporting consciousness in a way that is difficult to reproduce now.
And Wengrow was watching it all from inside the occasion.
"It was a great day. I remember the atmosphere, obviously, and being able to be there as a guest of the FA.
"And then afterwards, being able to go into the area where the people connected with the game were, and then going out into London and seeing the celebrations.
"That was something you just didn't forget."
Six decades later, the final remains one of the most scrutinised matches in football history, particularly Hurst's second goal, the ball striking the crossbar and bouncing down before being awarded by Swiss referee Gottfried Dienst on the advice of Soviet linesman Tofiq Bahramov.
But Wengrow's recollection is not that of someone who has studied the footage repeatedly or reconstructed the afternoon from television pictures.
He was there.
"I've been lucky because I've been at all the games where we've also lost major finals, European Champions League, for example, to Barcelona, and then FA Cup finals.
"But I've been able to enjoy every single Arsenal success over these last 60, 70 years.
"And I've been present to witness them."
The World Cup final therefore sits slightly outside the story of Martin Wengrow's Arsenal life, but it also belongs to it.
He was already an obsessive Arsenal supporter. He was already building the friendships with players and football figures that would eventually give him extraordinary access to the club's greatest teams.
And on one summer afternoon in 1966, those worlds collided.
"I want England to win, of course, but all my passion for football revolves around Arsenal.
"But that was a great day.
"It was very memorable."
And then, as if witnessing England win the World Cup at Wembley wasn't enough, Wengrow left the celebrations to begin another story that would last for the rest of his life.
"I took my wife out for the first time that evening."
Martin Wengrove's book "My Arsenal Life: Doubles, Invincibles, Glory and Despair" is from Pitch Publishing - which is available here.
