Derby County's Premier League pedigree isn't exactly one to be proud of.

They currently sit fifth in the Championship, and could mark their return to the big time after a decade-long absence with a successful playoff campaign.

Should they gain promotion, they must do better than their last attempt at staying in the top flight.

That attempt was so bad that it is widely regarded as the worst season for any team ever in Premier League history.

But what made it so bad?

This current season, it is West Brom who have disappointed the most, sitting rock-bottom on 20 points in early April, 10 from safety and with only six games left to arrest the slide.

As poor as they have been, the Baggies still have the faint glimmer of hope that they can still mathematically earn safety in the matches they have left.

Still, it has been a truly awful season for the Midlanders, but it is nothing compared to the suffering of Derby in the 2007/08 season.

By this point the Rams had already been relegated, a record for the Premier League-era.

They managed only 11 points and a goal difference of -69 - their sole win during the entire campaign was a 1-0 victory over Newcastle United in September.

Billy Davies oversaw that win and also their surprise promotion the season before, but was unceremoniously relieved of his duties in November 2007.

Paul Jewell took the hot-seat, but failed to win a single league match and earned less points than his predecessor, even going so far as to criticise his own players after the 4-0 drubbing at the hands of Reading on the final day.

Top Videos of the Day

Further statistics make for even tougher reading.

£3m signing Claude Davis made just 19 appearances throughout the whole campaign - Kenny Miller was their top scorer, but even he only managed four goals.

Even with Miller's quartet of strikes, the Rams only scored a dismal 20 league goals.

Derby have not returned to the big time since and, even after all this time, fans of the club will still be scarred by that soul-crushing season, with Derby widely regarded as the worst Premier League side of all time.

If they do get promoted, how can they avoid a repeat performance?

Mistakes happen, but they need to be learned from.

Current boss Gary Rowett has a good squad at his disposal - one that is certainly strong enough to get them out of the Championship, but can it make the step-up to the top flight?

Without the right additions, probably not.

Derby's failure a decade ago was at least in part due to a lack of investment in Premier League-quality players.

If they study their awful season of 2007/08, and strengthen properly during the summer, then there is no reason why the Rams couldn't consolidate themselves as a Premier League side if they were to gain promotion.