It's the long-forgotten cup final.

It's the cup final that some dare not speak its name.

The 1970 European Cup final between Celtic and Feyenoord has become, in theatrical terms, the Hoops version of ‘The Scottish Play’.

Jock Stein’s side were going for an unprecedented second European Cup triumph in the space of three years after the Lisbon Lions' triumph.

The Hoops' glorious victory in the same competition against Inter Milan in 1967 saw them become the first British team to capture European football’s glittering prize.

This was a chance for Celtic to really cement their place at European football’s top table and establish themselves as one of the greatest sides of that era.

Sadly, it was not to be.

Celtic had to endure the ignominy of exiting stage left as the not-so-gallant losers as Dutch outfit Feyenoord milked the applause and took their bow in Italy’s San Siro Stadium as they claimed a 2-1 victory.

If Celtic had reached their zenith in Lisbon in 1967, Milan in 1970 was most certainly their nadir.

51 years on and the mourning surrounding that loss continues.

Did Celtic under-estimate Feyenoord?

Did the Hoops row about commercial deals after many players felt that they were not suitably recompensed for their historical making feat in Lisbon?

Did complacency creep in?

What led to legendary managerial figure Stein questioning his own judgements?

Where did it all go wrong?

After all Celtic had comfortably disposed of Don Revie’s seemingly unbeatable and invincible Leeds United 3-1 over two legs in the semi-final.

The sense of euphoria after downing Leeds United was almost palpable.

It also led to some claims of premature celebration amid claims that Celtic had already won the trophy because they felt they had eliminated their biggest threat left in the competition.

Celtic were now entering unchartered territory.

Suddenly they were the overwhelming bookies favourites to lift the European Cup against the hitherto unknown Dutchmen.

It was a position that didn’t suit them well.

It is also widely recognised that the Hoops were comprehensively dismantled by a team that was, on the night, superior in every department and which was far better than anyone had been prepared for.

A kind of ‘Vorsprung Dutch Technik’ – if you will.

To all intents and purposes this was a complete role reversal of the events that occurred in Lisbon 1967.

That night in Portugal, Inter Milan were the fall guys.

In Italy, it was the Hoops' turn to be cast as the villains of the piece.

There was an overriding feeling that Celtic had treated Feyenoord lightly and underrated them at their peril.

Yet Feyenoord’s win would herald a golden period for Dutch football which would see their club sides win the European Cup four times - Ajax would win the trophy from 1971-73 - and the Netherlands national team reach two World Cup finals by the summer of 1978.

It is also a little-known fact that Rotterdam’s finest ever team provided seven of the Dutch 1974 World Cup squad (Wim van Hanegem, Rinus Israel, Wim Jansen, Theo de Jong, Wim Rijsbergen, Eddie Triejtel and Harry Vos), while six played for Ajax.

The difference, arguably, between the two clubs, was the mighty and mercurial talent of Johan Cruyff.

Ironically it was Jansen – who would go on to boss the Glasgow side in season 1997/98 and famously shatter Rangers dreams of 10-in-a-row – that put the shackles on Celtic talisman Jimmy Johnstone in the San Siro.

Celtic Way: Jimmy JohnstoneJimmy Johnstone

Despite taking the lead through Tommy Gemmell’s free-kick on 29 minutes - which saw the full-back earn the distinction of scoring in two European Cup finals – the Hoops were pegged back on 31 minutes as Rinus Israel netted a headed equaliser for Feyenoord.

The Dutch dominated proceedings from start to finish and it was no surprise when Swedish striker Ove Kindvall netted a late extra-time winner with just three minutes left on the clock to stun the Celts.

Defeat signalled the beginning of the end of the Hoops European dominance in football.

The Lisbon Lions had indeed roared but Celtic would never again reach the dizzy heights at the top of European club football’s summit.

The 1970s would still see the immense homegrown talent emerging at the club with the likes of Kenny Dalglish, Danny McGrain, Lou Macari, Davie Hay, George Connelly and Pat McCluskey earning the nickname the ‘Quality Street’ gang.

They would all stamp their authority one way or another in Stein’s team moving forward.

Celtic would go on and reach the semi-final of the European Cup in both 1972 and 1974 losing to Inter Milan and Atletico Madrid respectively.

A solitary quarter-final appearance and loss against Real Madrid in 1980 is the furthest Celtic have gone in the competition in the guise of the European Cup and the Champions League since those halcyon days of the 1970s.

Feyenoord boss Ernst Happel - who masterminded the Rotterdammers unlikely victory - had outfoxed Stein just as the Scot had outthought Inter Milan coach Helenio Herrera in 1967 said: “I felt we deserved to win.

“I was pleased with the way Mr. Stein accepted it.

“He was one of the first to congratulate me.

“This is sportsmanship.”

Dutch midfield maestro Wim Van Hanegem also commented: “Jimmy Johnstone came up to me at the end of the match, a tough battle it had been, and told me we deserved to win and wished us all the best.

“You’re a big man if you can react like that after losing a European Cup final.”

Celtic had inexplicably imploded on the greatest stage of all.

That fateful night in San Siro the Hoops did not bargain on Feyenoord pulling off one of the greatest ever shocks in European club football.

A tragedy of Shakespearean proportions was certainly not in the script on a night when Celtic were supposed to claim an historic European Cup winning double.

Stein’s men ended up with nothing more than: “Double, double toil and trouble; Fire burn and cauldron bubble.”

‘The Scottish Play’ indeed.

It is fair to say it was a definite case of bad form rather than bad luck cursing Celtic and Stein in their bid for two European Cup crowns.

Time may well be a great healer.

Yet no poultice has ever treated the wounds and scars inflicted on Celtic by Feyenoord over 50 years ago.

It is little wonder that the 1970 European Cup final remains a silent footnote in Celtic's glorious and illustrious history to this day.