Portsmouth may be in League One right now, but there was once a time where the south coast club were an established Premier League outfit.

Pompey were promoted to the top flight under the guidance of Harry Redknapp in 2003, and his managerial acumen saw the club become a solid outfit for a number of years.

Unfortunately though it all ended up falling apart thanks to some questionable changes in ownership, lots of managerial changes and a heck of a lot of money wasted on players.

There's no doubt that some of the money spent was well invested though - profits were made on big players such as Glen Johnson and Lassana Diarra and some of the business got Pompey into Europe in 2008 after winning the FA Cup.

Let's take a look at the top 10 most expensive arrivals at Fratton Park in the club's history, and it will come as no surprise that they all come in the era where they were flying high in the top flight.

Yakubu was a bit of a surprise signing in 2003 for Pompey, with the club taking him from Maccabi Haifa initially on loan for the second half of their Championship-winning season.

The Nigerian had scored seven goals in the Champions League that season so to play in England's second tier seemed like a bit of a demotion for him, but after scoring seven times in 13 games to secure Pompey's promotion, Yakubu made the switch to Fratton Park permanent for £4 million.

After scoring 29 goals in two full Premier League seasons for Pompey, Yakubu made the switch to Middlesbrough in 2005 and then moved onto the likes of Everton, Blackburn, Guangzhou City and others.

Retiring in 2017, Yakubu went on to become a football agent, and told Portsmouth News last year that he coaches his clients every week in the local park near his home.

There was a lot of bad business done towards the end of Portsmouth's time in the Premier League, but one bit of good business was the signing of Glen Johnson from Chelsea in 2007 after an initial loan spell.

Johnson was a part of the FA Cup winning team in 2008 and it was at Pompey where he established himself as an England international.

His good performances continued in 2008/09 and they were recognised with a place in the PFA Team of the Season - and that led to interest from bigger clubs for his signature.

He did eventually depart for Liverpool in 2009 for £17.5 million - some profit considering he only joined Portsmouth for £4 million - and nowadays Johnson is doing punditry work after retiring from playing in 2019.

Only second to Yakubu in terms of Premier League goals for Pompey, Benjani was recommended to Harry Redknapp by Arsene Wenger in 2006 and subsequently purchased the Zimbabwean striker for £4.1 million.

Benjani had an unsuccessful first half season with Pompey in terms of scoring and only scored six times in his first full campaign, but the 2007/08 season saw him become prolific, netting 12 times in 23 games and that got the attention of Manchester City.

City captured Benjani in the 2008 January transfer window, but he wouldn't be a success there and following a stint at Blackburn Rovers, Benjani returned to Fratton Park briefly in the 2011-12 season.

Nowadays, Benjani is obtaining his coaching qualifications and spent time in 2020 with Pompey's under-16's, who his son plays for.

Nugent was hot property in the summer of 2007, having been at Preston North End for two-and-a-half seasons and obtaining his first England cap, and it was Pompey who beat Sunderland to his signature for an initial £4.5 million.

In what was a strange first few weeks at the club, Nugent was allowed to leave if he wished with Derby County pursuing him, and that set the tone for an unsuccessful Premier League spell for the Scouser.

Nugent scored just three goals in 34 top flight appearances for Pompey but he was more successful in his sole season in the Championship for them where he netted 13 times.

Now 35 years of age, Nugent is on loan at League Two side Tranmere Rovers from Preston North End, having returned to Deepdale in 2019 on a two-year contract.

After falling out of favour at White Hart Lane, Kaboul was purchased by Pompey for £6 million to strengthen their hand for the upcoming UEFA Cup campaign.

The Frenchman always had little spells where he would pick up injuries, and because of that his first season saw him play just 20 league games, but after impressing in his year-and-a-half at Fratton Park he was re-signed by Tottenham in January 2010.

Kaboul went on to play for Sunderland and Watford and hasn't played football since 2018 - he hasn't officially retired though but in 2020 said he was 'taking a break' from football in order to pursue coaching.

Diarra arrived from Arsenal halfway through the 2007/08 campaign for a fee of £6.25 million, having failed to breakthrough into the starting line-up at the Gunners.

At the age of 22 though there was still clearly time for Diarra to develop and that's what he did - he became a key fixture and secured his place in France's Euro 2008 squad and his Pompey performances attracted interest from massive clubs.

One of those - Real Madrid - captured him just a year after he joined Portsmouth, taking him to the Spanish capital for a fee of £19 million, representing healthy profit for the English club.

Diarra went on to play in Russia, the UAE and back in France, eventually finishing his career in 2019 at Paris Saint-Germain.

Upon his arrival at Pompey in 2007, Utaka became the club record signing having joined from Rennes for £7 million.

Unfortunately for Portsmouth though his goal record didn't end up matching that price tag - nor his reported weekly wage of £80,000 (although the Nigerian refuted those figures).

Utaka spent three-and-a-half seasons at Fratton Park, scoring 10 league goals before returning to France with Montpellier.

Having played for a number of clubs in Turkey, Egypt and France since then, Utaka retired and took up a youth coaching role at Montpellier last year.

Utaka may have been a bit of a bust, but a player who arrived in the same transfer window wasn't in the form of Sulley Muntari.

The Ghanaian midfielder joined for a fee of £7.1 million from Udinese and established himself as a top Premier League midfielder in his one-and-only season at Fratton Park.

Muntari scored five times for the club and won the FA Cup, but he would move back to Italy just over a year after arriving on the south coast, with Inter Milan signing him for €14 million.

He did briefly come back to England with Sunderland, but Muntari would hop across Milan in 2012 to the red and black half of the city, and ended his career in 2019 with a brief spell at Albacete.

Defoe was a massive pick-up for Pompey in January 2008 after having his game-time restricted at Tottenham Hotspur, and he moved clubs for a fee of £9 million.

He was small in stature but big on scoring, and Defoe showed his natural prowess in his first half-season by scoring eight times in 12 games, and then eight in 17 league outings in the next half-season.

A full year after Defoe departed Spurs, the club wanted him back and it took £15.75 million for Portsmouth to part ways with him.

At the age of 38, Defoe is still playing - albeit sporadically - for Rangers in the Scottish Premiership and will take home a league winners medal this season.

In a deal worth up to £11 million, Crouch started a second spell at Fratton Park having signed from Liverpool in the summer of 2008 - six years after leaving the club previously for Aston Villa.

Like Defoe though, Crouch stayed for just one full year, scoring 16 times in 46 games but was unable to get Pompey out of the group stage of the UEFA Cup.

He would soon get a bigger taste of European football as he joined Tottenham in the summer of 2009, before going on to spend eight years at Stoke City.

Now retired from football, Crouch now runs 'The Peter Crouch Podcast' and hosts the 'Peter Crouch: Save Our Summer' show on the BBC.