The phrase 'sleeping giant' is one that has crept more & more into footballing parlance over the years, we take a look at some current outstanding examples.

Sheffield Wednesday and Leeds United have now spent a combined 28 years outside of the Premier League

Since the term 'sleeping giant' has become more common within the game of football, every country has an established idea of which are the truly top clubs, and which are the sleeping giants. The top clubs tend to spend large amounts of money each transfer window, have the best players and consistently compete for trophies.

The sleeping giants though are a more curious case, clubs who have the potential to challenge the top clubs but don't currently do so. Many of these have previously been top clubs before suffering a harsh or sudden fall from grace, whilst some have never tapped into their enormous potential.

We have compiled a list of seven of the most outstanding sleeping giants in European football, all of whom have the capability to challenge the top teams domestically and even in Europe, but due to certain factors haven't done for some time now.

Hamburg regularly competed for the highest honours in the 1970's and 1980's

Hamburg

The first of our seven clubs is Hamburg. The German outfit are not as lowly as some of the sides on this list, but they're still a long, long way off where they used to be and could still be. Not even a shadow of the great Hamburg sides of the 1970's and 1980's, during which time the club won 3 Bundesliga's, 2 DFB-Pokal's and one European Cup, this current squad is more used to fighting relegation battles than fighting for European honours.

They have finished in the bottom 4 in the Bundesliga in 3 of the last 5 seasons. Despite their lack of success, Hamburg still have enormous support, with an average attendance of 53,700 last season, higher than that of Ajax, Atletico Madrid or PSG. Hamburg still maintain the distinction of being the only team to have played in every Bundesliga season, but with the right leadership they could return to the summit of German football.

Leeds United team photo before facing Barcelona in 2000

Leeds United

Leeds United's golden age came around a decade earlier than that of Hamburg's, under the stewardship of Don Revie. Despite Leeds fans taking great delight in their successes in the 1960's, 70's and 90's, the club are actually perennial underachievers. Technically the third biggest city in the United Kingdom behind London and Birmingham, with a population of over 750,000, Leeds United are also the only club in the city of Leeds.

Yet their three league titles is the same as that of Huddersfield, their one FA Cup win less than that of Bury and their one League Cup win the same as that of Luton or Swindon. Leeds has the potential to compete with England's elite, but they have now spent 12 years outside the top flight, 3 of those spent in League One, and look no closer to a Premier League return.

Leeds United don't look close to a Premier League return

Fortuna Dusseldorf

With a population of over 600,000, Dusseldorf is bigger than Dortmund, home to one of Germany's footballing powerhouses Borussia Dortmund. Fortuna Dusseldorf have only actually won one German championship in their history, but they regularly competed at the top of the Bundesliga and in Europe during the 1970's.

In such a large city with such a fantastic arena which holds 54,600 fans, there's no doubting that Fortuna have the infrastructure in place to compete with the titans of German football. However, it has now been over two decades since the team was even remotely competitive, spending just one season in the Bundesliga in that time and dropping as low as the fourth tier.

Torino in action against Hull City

Torino

It has historically been claimed that there are only two cities in Italy where Juventus are the best supported team; Florence where it is Fiorentina and Juventus' home of Turin, where it is Torino. Whether that is still true it is difficult to be sure, but there is still enormous support for Turin's supposedly 'lesser' team within the city of almost 900,000 people.

Torino have a fine history, most notably the Grande Torino team of the 1940's, who won five Serie A titles in that decade, before all being tragically killed in the Superga air disaster of 1949. The club have spent a number of recent seasons in Serie B, and although back in Serie A, they still finished in the bottom half last season. Perhaps the signing of Joe Hart can turn their fortunes around.

Sheffield Wednesday's absence from England's top flight currently stands at 16 years

Sheffield Wednesday

The second English club to make this list, Sheffield Wednesday came close to making a return to the Premier League last season, but were ultimately beaten at Wembley by Hull City. Sheffield, like Leeds, is a very large city, and whilst Wednesday do have to compete with neighbours United, the thirst for football in Sheffield is such that the city could comfortably accommodate two top teams.

As it happens, they don't have one right now. Sheffield Wednesday have spent 16 years outside the Premier League, 4 of those in the third tier, whilst neighbours Sheffield United have spent 9 years outside the top flight but are currently in League One. Wednesday supporters may be worried that they could have missed a great opportunity last season, with the likes of Newcastle, Aston Villa, Norwich and others to compete with this season.

Sheffield Wednesday manager Carlos Carvalhal reached the play-off finals last season

RC Strasbourg Alsace

Strasbourg are a club which have been plagued by the same troubles that Alsace as a region has been. The club has changed nationality, and as such, leagues, three times over their 109 year history. With the exception of the very small club FC Mulhouse, Strasbourg are the only football club in Alsace, a region with a population of 1.8 million people.

Given such a wide reach, Strasbourg have the potential to become a major force in France but have recently played in the fourth tier of French football, playing against mostly amateur and a few semi-professional sides. The club still have a stadium with a capacity of nearly 30,000 and were promoted to Ligue 2 last season. Having had a bright start to the season, Le Racing's rise could well be well on course.

Despite being the capital of Germany, Berlin has a poor footballing past

Hertha Berlin

Berlin has always been something of a footballing anomaly. The German capital and home to over 3.5 million people, Berlin has failed to produce a genuinely successful football team. Not since 1931 has the club lifted a league title, and in the last six years the club has bounced between the Bundesliga and the 2. Bundesliga.

A seventh placed finish in the Bundesliga last season represented clear progress, but a city like Berlin should have a team competing among Europe's elite, not middling in the centre of the Bundesliga table. Two wins from two so far this season is hopefully a sign of things to come.

Championship outfit Newcastle United are another of Europe's sleeping giants, but who would you say has the greatest potential?