England Under-21s manager Gareth Southgate believes this summer's Toulon tournament will be an "invaluable" experience for his players, considering the way they have dominated their European Championship qualifying group.

The Young Lions - whose 2013/14 squads have included Saints midfielder James Ward-Prowse - sit six points clear of Moldova at the top of Group One with just three matches remaining, having racked up six wins and 24 goals during an unbeaten seven-game sequence.

Southgate's side are almost certain to reach the play-offs but the Under-21s boss knows beating European minnows is hardly a yardstick with which to measure success, highlighted by the way they performed so badly in Israel last summer after a fine run of form.

As a result, the Young Lions will be playing at the Toulon tournament in France next week, where they will pit their wits against Brazil, Colombia, Qatar and South Korea in their initial four group games.

"It is invaluable playing teams from different continents," Southgate said.

"We play mainly at this age group European teams. We think we need to expose our players throughout the age groups to more South American, North American, African and Asian teams.

"It is an important thing for their development and we want tough challenges. It is no use ducking the big opponents. We want to play the best teams and test ourselves against the best teams.

"Only then will we know exactly where we are so that was important for us this summer."

Under-21s regulars Tom Ince, Jesse Lingard, Wilfried Zaha and Burnley's Southampton-raised striker Danny Ings are unavailable for the tournament as they are too old.

The quartet have, though, been named in Southgate's 25-man squad as they are eligible for tonight's European Championship qualifier against Wales - a match for which Southgate has a number of players unavailable due to injury or involvement in club matters.

"It can change very quickly," he said. "We've got three away games to finish the group with, which will be challenging.

"We've got a few new players coming in so you're not totally certain how that is going to pan out.

"We set off at the start to play a certain brand of football and to try and win while playing that brand of football. That will be our aim again on Monday night.

"We focus on performance and the way that we play and if you do that then results are a by-product of that."

Liverpool defender Brad Smith is one of the new call-ups but may well be rested for the Wales match, while Manchester United goalkeeper Sam Johnstone is unavailable and Wilfried Zaha has also withdrawn.

"There is nothing serious," Southgate said. "Liverpool played on Wednesday and Brad Smith played the full 90 minutes so he might take a little longer to recover from that.

"Sam Johnstone may well be one that we have to assess because he has been carrying an arm injury. It may be that he has to go back.

"Everyone else up to this point is available for selection."

Ward-Prowse could be up against his Saints colleague Lloyd Isgrove tonight.

Isgrove ended the season gaining experience at League 1 club Peterborough, who were beaten in the play off semi finals by Leyton Orient.