Why take Harry Kane and Ross Barkley to European Under-21s?

Kane celebrates his debut England goal with Danny Welbeck and Ross Barkley

England Under-21s enjoyed a thrilling win over their German opponents on Monday, giving the strongest indication yet that Gareth Southgate's side are building momentum ahead of this summer's European Championship.

The fact they came back from 2-1 down to win 3-2 without some of their more recognised players, such as Tottenham's Harry Kane or Manchester United's Luke Shaw, underlined the new-found spirit in the squad.

It's a far cry from two years ago when Stuart Pearce took his squad to Israel and watched them lose all three Euro 2013 games with a disjointed group and reports of attitude problems among some players.

Contrastingly, Southgate says he has no doubts about his team's character. An exciting crop of players has enjoyed an unbeaten qualifying campaign, so there is a sense they could be real contenders in the Czech Republic in June.

But as Pearce experienced in 2013, the biggest problem could be whether Premier League clubs allow their players to be released.

So why should the likes of the Premier League's top scorer Kane, Shaw and perhaps even Everton's Ross Barkley be allowed to play for the Under-21s this summer if they have already played for the senior team?

Who should go?

A potential starting XI at this summer's European Championships - but is it likely?

There is a careful balancing act to be performed by Southgate when it comes to picking his 23-man squad.

Former England striker Gary Lineker said it would be a "national disgrace" if England's best youngsters did not appear at the European Championship, yet consideration must also given to the players who have helped Southgate's team qualify.

The former Middlesbrough boss has said there might be only two vacant places in the squad. "I know whoever goes is totally committed," he said. "There won't be any loafing around, there won't be any lads who feel it's a chore to go."

England could flood their Under-21s team with an impressive cast of players who have already competed for the seniors: Kane, Barkley, Liverpool's Raheem Sterling, Manchester United's Phil Jones, Arsenal winger Alex Oxlade-Chamberlain and even his club-mate Jack Wilshere, whose birthday is on the deadline for the oldest players allowed to compete in the tournament.

But even though senior manager Roy Hodgson has softened his opposition on players returning to the Under-21s having represented his team, it seems as if Southgate will stick with those who have helped his side qualify.

That could rule out Barkley, whose form has dipped this season after appearing at the 2014 World Cup in Brazil, and has not played for the under-21s since. Derby's Will Hughes is likely to be his replacement.

But it would include Kane, who scored six goals in eight games during qualifying, so long as his club allows him.

Alongside the 21-year-old Spurs striker, Norwich winger Nathan Redmond and Manchester United's Jesse Lingard, on loan at Derby, have added thrust to the England Under-21s attack. Southampton's James-Ward Prowse and Chelsea's Nathaniel Chalobah, on loan at Reading, have been steady influences in midfield.

In defence you can add in Everton's John Stones, Tottenham's Eric Dier and West Ham's Carl Jenkinson. In attack there is West Brom's Saido Berahino and Burnley striker Danny Ings, so there is plenty of Premier League experience that Southgate can rely on.

Springboard to senior success

Mesut Ozil and Sami Khedira celebrate winning the 2009 Under-21s European Championship

Historical evidence suggests that teams who have success at the Under-21s Championship, enjoy further riches down the road.

Germany, who won the 2009 tournament after beating England 4-0 in the final, had five players in their squad who were also involved when the senior side won the 2014 World Cup in Brazil.

Italy, who are the most successful side in the European Under-21s Championship's history, picked five players in their 2004-winning squad who went on to compete in the 2006 World Cup win in Germany.

Although Spain's success at under-21s and senior level has occurred concurrently, the 2011 European Under-21s triumph featured midfielders Juan Mata and Javi Martinez before they went on to win the European Championship with the seniors in 2012. The fact they had already been selected in the 2010 World Cup winning squad showed their willingness to drop down to the younger category a year later.

As England goalkeeper Joe Hart, who also played in the Under-21s, said recently: "We have all seen the blueprint of Germany and you can't look past that. It's quite inspirational and I'm sure Gareth Southgate will be alluding to that when he is drawing people to play for the Under-21s side."

Benefits for the players

Gareth Southgate has suggested he will stick with the players who have helped England qualify

Success breeding success is not a concept solely associated with other European nations.

As many as 13 of Southgate's potential England Under-21s squad could be made up of players who won the European Under-17s Championship in 2010.

That squad consisted of Berahino, Chalobah, Stoke goalkeeper Jack Butland, Everton's Luke Garbutt and Middlesbrough defender Ben Gibson, who are all likely to picked this summer.

Whether it's playing every few days in pressure games, coming up against unfamiliar tactics or styles, or even penalty shoot-outs, there is much to be gained by playing opposing countries in tournament conditions.

"Tournament football is our Achilles heel," says Pearce, who cites Shaw as an example of a player who was taken to the 2014 World Cup in Brazil without previously representing the Under-21s at the Euros.

Crystal Palace winger Wilfried Zaha, one of Pearce's squad two years ago, said at the time: "It's not that we didn't try hard enough. It's maybe we weren't used to playing in tournament games under so much pressure. We didn't expect all that quality."

It will be hoped that the current group use their experience to avoid the same naivety.

Opposition from the clubs

Mauricio Pochettino says he understands Kane's desire to play for England

So if it appears that there is everything to be gained from a players' perspective, why the opposition from the clubs? It is no coincidence that the highest-profile players have drawn the most resistance.

England's record on this issue does not set a great example.

Two years ago, Pearce complained that up to 13 players withdrew from his squad, whether through injury or "apathy".

And the former England Under-21s boss warns that if Barkley is not selected he would be stuck in "no-man's land" between the two England teams, despite Everton boss Roberto Martinez insisting his player needs a "proper break" this summer.

Spurs boss Mauricio Pochettino feels that Kane could also suffer from burnout after scoring 19 Premier League goals this season to help boost his side's Champions League charge. And yet the club's post-season tour of Malaysia and Australia has highlighted other potential agendas.

Former England defender Danny Mills rejects the notion that 21-year-old players need to rest, and says that pressure on young players can add to the indifference that Pearce has witnessed.

"Pochettino will put Kane under enormous pressure as all big clubs and managers do," Mills said. "But look at the Germans and Spanish - they always play under-21s tournaments.

"We have to create a culture where players want to play."

Fortunately for Southgate, that appears to be changing and it comes at a time when changes to a more possession-based style appear to be bearing fruit at the age-group level.

Leading the way is Kane, who has become a poster boy for those reforms and has said he wants to play for England whenever he can.

Although Pochettino's concerns are obvious, he also recognises the importance of competing for your country as he did in earning 20 caps for Argentina.

"Maybe I'd prefer that Harry has a month's holiday after the season to rest," he said. "But we realise we need to support the national team and to take the best decision for us all."

If Southgate can persuade Pochettino that the interests of the Premier League's top scorer are best served by playing for England this summer, he will have a great bargaining chip for any other refuseniks who have been less impressive this season.