Stephen Craigan has long been prepared to argue on David Turnbull's behalf – now he says it is time the Celtic ace fought his own battles if he wants to convince Steve Clarke to make him a key man for Scotland this summer.

Craigan played a key role in the 21-year-old's path to Parkhead stardom when he was his Under-20s coach at Motherwell.

The former Fir Park skipper had such faith in Turnbull's abilities he even found himself at loggerheads with former first-team boss Stephen Robinson and Scotland Under-18s coach Donald Park as he demanded to know why the midfield playmaker was not being selected.

Clarke took some convincing himself but has now handed the PFA Scotland young player of the year a call-up for his 26-man Euro 2020 squad.

And Craigan is certain it is a decision the Hampden boss will not regret.

"I had David for two-and-a-half years just before he came into the first-team," said the Premier Sports pundit.

"That's the small part I played in his development but there are others before and after me who have helped him too.

"But yeah I did phone Donald Park because having watched the U20s league when David was only 16 or 17, I just felt he was the stand-out player.

"Anyone who came to watch my side would say, 'Who's your number 8? He's some player'. I remember Neil Lennon doing it after we played Hibs Under-20s and Lenny eventually ended up signing him for Celtic.

"I played him in the Youth Cup final when David was just 16 against guys aged 19 and 20. I wasn't trying to test him out or see how he'd react. I knew he was good enough.

"Stephen Robinson and I had plenty of heated discussions because I felt he should have been in the first team before he was.

"Ultimately Stephen managed him best because he put him in the team when he was ready and he flourished.

"I understand it can be difficult for first team and international managers to throw in young players because it's a results-driven business for them.

"But David has shown at every level he's stepped up to, he's been ready for it.

"That's why I've no doubt you could put him into a game like the one at Wembley next month against England and David will just be like, 'Give me the ball'. That's what he does. He has a temperament that allows him to thrive.

"I'm not saying Steve Clarke will start him but if he looks at his bench and needs a moment of magic and someone to be fearless in a red-hot atmosphere, I genuinely believe David's temperament will allow him to do that.

"The Celtic players have learned early on they can trust him with the ball. The Scotland players will soon discover for themselves they can trust him too. If they give him the ball he'll look after it."

But while Craigan has no doubts at all over Turnbull's abilities, he warned the Hoops youngster and fellow uncapped call-ups Billy Gilmour and Nathan Patterson they must now prove they are worth a place in Clarke's team by doing this business day in, day out in training.

"When David wasn't called into the squad for the games in March, in my mind that was him ruled out of going to the Euros," said former Northern Ireland international Craigan.

"But it's nice to see him getting his chance alongside Billy Gilmour and Nathan Patterson.

"We want to see our young players getting the chance to go to a major tournaments. I mean some great Scottish players have never had that opportunity – Barry Ferguson, Scott Brown, Darren Fletcher, Allan McGregor, James McFadden. Guys who put so much in for their country but never got the chance to showcase their talents at a big tournament.

"But these young guys will embrace the challenge ahead. All three are at big clubs, so they won't be fazed.

"But they have got to be greedy and say, 'I'm not here to make up the numbers. I want to show every single day I'm ready to play if called upon'.

"When David moved to Celtic I thought a few of their players would be surprised at how good he was on the ball. And I think a few Scotland players will be surprised too.

"These games at the Euros could end up boiling down to one moment, someone providing that bit of quality than can get you a goal. I think David has got that."