Once eternally marooned in the mediocrity of midtable but now knocking on the door of the Premier League's summit, Tottenham Hotspur's transfer history certainly makes interesting reading.

Indeed, the Lilywhites' list of recruits via the transfer market is about as vast and varied as it gets in the Premier League, ranging from utter flops like Portugal front-man Helder Postiga to incredibly shrewd additions such as midfield maestro Luka Modric.

Spurs were the English top flight's busiest club on summer deadline day and their late window flurry has got us at FootballFanCast thinking about their record in the transfer market - most specifically, their 10 most expensive signings of all-time.

And for every impressive addition made by Daniel Levy and his predecessors, there's also been an absolute gaffe - often setting back the north London club a small fortune. With a little help of our friends at TransferMarkt, here's a rundown of Spurs' ten costliest signings.

10. Mousa Dembele

The Lilywhites forked out just over £16million for Mousa Dembele's services four summers ago and his White Hart Lane career has taken an interesting path. A fantastic debut season was followed by two campaigns in the wilderness but the Belgium midfielder has been a real force under Mauricio Pochettino and is now seen as arguably the most important component of Spurs' engine room.

Verdict: Hit

9. Paulinho

Paulinho was meant to be the signing that propelled Spurs towards the Premier League title race. But the Brazil international, who impressed at the Confederations Cup, never quite turned up at White Hart Lane, producing the occasional goal yet being largely anonymous in midfield. Just two years after his £16.77million arrival, he was sent packing to the Chinese Super League.

Verdict: Flop

8. Luka Modric

It's rather incredible to think Spurs paid just £17.85million for Luka Modric, considering he's gone on to establish himself as one of the best midfielders of his generation and lift two Champions League titles with Real Madrid. Indeed, after four affluent seasons with the Lilywhites, the Croatian playmaker completed a deserved £30million move to the Bernabeu.

Verdict: Hit

7. David Bentley

A signing Spurs fans would rather forget. Tottenham paid a massive £18.7million for David Bentley in 2008 and a significant chunk of that fee went straight into the pockets of north London rivals Arsenal - where the winger started his career. Bentley made 62 appearances for Spurs, decided he didn't like football and retired at the age of 29 - but not before seeing out the entirety of his five-year White Hart Lane contract.

Verdict: Flop

6. Vincent Janssen

One of the more recent arrivals in this top 10, Spurs paid £19million for Vincent Janssen's services during the summer. The Dutchman holds up the ball well and has presence in the final third, but he's yet to find the net in open play.

Verdict: Hit (but he could yet prove us wrong)

5. Darren Bent

Darren Bent's Spurs career was short and sweet, netting 18 times across two seasons after arriving from Charlton Athletic at a cost of £21million. But the English striker couldn't quite settle in north London and eventually left for Sunderland in a £10million deal that later rose to £16.5million. Overall, Tottenham fans were left a little underwhelmed.

Verdict: Flop

4. Roberto Soldado

Tottenham's horrendous transfer record in the striker department continues with Roberto Soldado taking fourth place in the top 10. Not exactly a star of La Liga and clearly ill-equipped for the Premier League, many were surprised when Spurs forked out £25.5million for the Spain international. He managed just seven Premier League goals in two seasons, most being from the penalty spot, before returning to his homeland with Villarreal. He's not been the same player since.

Verdict: Flop

3. Erik Lamela

Erik Lamela appeared resigned to going down in the history books as one of the Premier League's all-time flops after arriving with a £25.5million price-tag, until Mauricio Pochettino took the Spurs helm. Indeed, the Argentine has somehow got the best out of his countryman, discovering an unexpected work-ethic, and Lamela is now an important member of Spurs' first team squad, filling in across the attacking midfield berth.

Verdict: Hit

2. Heung-min Son

Heung-min Son hasn't quite met expectations at White Hart Lane, fading in influence as his debut campaign dragged on following a £25.5million move from Bayer Leverkusen. But the South Korea international's talent is undoubted and his return of five goals in seven appearances across all competitions this season is nothing to be sniffed at. He appears to be growing in importance under Pochettino and at the age of 24 looks a decent long-term investment.

Verdict: Hit

1. Moussa Sissoko

Easily one of the most controversial transfers of the summer, Spurs paid a staggering £29.75million for Moussa Sissoko. That makes him Tottenham's club-record signing, a rather unusual scenario for a versatile midfielder who doesn't claim an immediate place in the starting XI. Sissoko's notoriously lackadaisical attitude suggests this deal could soon backfire for the north Londoners.

Verdict: Flop