Diamonds are forever? John Martin is wondering where many of them have gone. During 19 years as the Airdrie custodian, madcap Martin racked up 658 appearances between the posts for the Lanarkshire side, which is marginally more than the club’s average attendances these days.

In Martin’s pomp, Airdrie, particularly under the canny stewardship of Alex MacDonald in the 1990s, were a robust, resilient outfit possessing the kind of stubborn, awkward menace you’d get with a stone in your shoe.

The giddy highs of two Scottish Cup final appearances, against Rangers in 1992 and Celtic three years later, illuminated Martin’s long stint. In those two showpiece occasions, Airdrie gave both sides of the Old Firm a right good run for their money.

The halcyon days seem so far away now, you just about have to scroll through the microfiche of the North Lanarkshire archives to find dog-eared evidence of cheerier times.

This weekend, Airdrie travel to the east end of Glasgow to face Celtic in the fourth round of the William Hill Scottish Cup. Upsetting the odds used to be an Airdrie speciality. Martin is not betting on any surprises against the holders on Saturday, though.

Indeed, as he watches his old club splutter on in League One, the 60-year-old offered a sighing, reflective assessment of Airdrie’s downturn in fortunes over the seasons.

“Does the decline of the club sadden me? Yes, it’s the whole package,” he said. “I’ve been through there to watch the games and I

just think ‘who is this?’ It’s just the way I feel.

“You’re lucky if there are 600 people there. If they play Raith Rovers you will maybe get 1000 people there. I think it’s not the same fanbase we had. When we played at Broomfield we would have 10,000 or 12,000 fans there and the atmosphere was great.

“Maybe some of them have passed away or not gone back. It makes me wonder where the fans have all gone. Is it because the team’s not good enough? Do the fans like the board? It could be a number of things. I would love to see the passion from the fans for the club coming back.

And what about Airdrie living up to that old adage that the cup’s a great leveller and springing a surprise?

“If Airdrie win on Saturday, it would be bigger than any result the club achieved in my time as a player, without a shadow of a doubt,” he added.

“If they are going to win against Celtic they need to keep the fans quiet for the first 25 minutes and then hope for a breakaway.

“They will need to frustrate them. I hope it will happen but if I’m honest it’s not going to happen.”