FROM listening to Neil Lennon and Peter Lawwell over the past few days, it has been pretty obvious that the pair of them are resigned to losing some of Celtic's crown jewels this summer.

Supporters have also read between the lines and reconciled themselves to the probability that Gary Hooper, maybe Victor Wanyama, and even Fraser Forster are nearer the end of their Celtic careers than the beginning. The issue for the club is not whether they will lose these guys – they'll all go, sooner or later – but whether they can continue the production-line alchemy which built one team good enough for the last 16 of the Champions League and will soon have to do so again.

Lennon – the subject of plenty of speculation himself – did an endless amount of talking to satisfy the media's demands last week but on Wednesday night he said something quietly profound to a handful of us in a room deep inside the Juventus Stadium. When asked if Celtic could continue their high strike rate in terms of excellent signings he struck to the heart of the matter: "Everyone looks at what we do and will copy or try to overtake it."

In other words, there will be rivals aggressively pursuing the very players Celtic hope to bring to Parkhead. Lawwell, Lennon and football development manager John Park don't get it all their way.

An unseen competition goes on permanently between scouts, and it's just as fierce and crucial as what goes on when the Champions League music blares and players do battle on the pitch. A defining characteristic of Lennon's nearly three years in charge has been Celtic's run of successful signings, and 10 in particular: Charlie Mulgrew, Joe Ledley, Gary Hooper, Biram Kayal, Emilio Izaguirre, Fraser Forster, Victor Wanyama, Kris Commons, Kelvin Wilson and Adam Matthews. You can bet that every Barclays Premier League club knew about each one of them before Celtic made their moves.

A perception has grown that, under Park's astute scouting operation, Celtic have scoured the planet picking unknown young talents from obscurity and turning them into players they can use and then sell on for millions. There is some truth in that but in fact the market they have raided most successfully is England, and nearly always the npower Championship. The most rewarding seam of talent has been British players between the ages of 19 and 25: Ledley, Hooper, Wilson and Matthews all came from England's second tier. Kris Commons can be added to that list albeit he arrived a little older, at 27. Mulgrew was in Scotland but, again, came as a 24-year-old British player. The same with Forster, from Newcastle reserves in the Barclays Premier League. Celtic have been linked with Michael Ngoo (the Liverpool reserve on loan at Hearts) and Charlie Austin of Burnley. At 20 and 23, they fit the template.

Neither have their best foreign signings been quite the big gambles they appeared to be. Few would have recognised Izaguirre when he came from Montagua in the Honduran league, yet he had already played for his country at the 2010 World Cup finals. Wanyama, too, was also an internationalist taken from the Belgian Jupiler League, a division comparable in status to the Scottish top flight. The last imported player signed by Celtic and sold on at vast profit was Ki Sung-Yueng, already a South Korean internationalist by the time he came to Glasgow under Tony Mowbray, aged 20.

When so many transfers strike gold, the club wins leagues and cups and pulls its weight in Europe, failed signings can be absorbed without criticism. Daryl Murphy, Freddie Ljungberg and Rabiu Ibrahim did not work. Efrain Juarez cost £3m and Mo Bangura £2.2m, and both failed. Miku and Lassad Nouioui have still to impress. But Celtic have a far better team now than on the day Lennon took over, despite him taking in around £23m in transfer fees and spending just over £17m. Aiden McGeady was sold for £9.5m, and Hooper and Wanyama could attract fees in that vicinity. The worry for Celtic is that even a scouting network as thorough and impressive as theirs is constantly up against it.

They appointed Park in 2007 after he helped develop James McFadden and Lee McCulloch at Motherwell, then Steven Fletcher, Kevin Thomson, Scott Brown, Steven Whittaker and Gary O'Connor at Hibernian. Celtic wanted the best they could get and the appointment of Park was fully vindicated. It takes time to build an international network of scouts and stringers, to compile endless dossiers and DVDs, even to gain expertise in how to quickly make travel connections and get to games in time to watch a potential signing in the flesh. It's about thoroughness, an intelligence network and player identification. "John is always working, 24/7," Lennon has said. "It's a constant turning of the wheel."

Gone are the days when Celtic could keep John Hartson for five years, Chris Sutton for six, Henrik Larsson, Stiliyan Petrov, Alan Thompson and Lennon himself for seven, and Paul Lambert for eight. Hooper has been with them for three years and Wanyama only two. Their sale, or the sale of others who will raise significant money to help reshape the squad, is an unfortunate but essential part of the Celtic model.

And what must nag at Lawwell, Lennon and Park is the fact that having assembled one team good enough to beat Barcelona, it doesn't get any easier to pull that off again.