The £20m West Ham transfer that could play right into Tottenham's hands

This was always going to happen eventually. You simply cannot play Championship football to the standard that Jack Clarke has for large swathes of this season and not expect to draw some kind of attention from the Premier League.

The Sunderland winger has been nothing short of sublime in recent months, and at times has felt like the only attacking force keeping the Black Cats in the promotion hunt. So far this term he has scored 12 goals in 26 league outings, and leads the division in terms of progressive carries. (Clarke has 217; the next best tally in the second tier is Kyle Walker-Peters' total of 153.)

It is unsurprising, then, that he is beginning to garner serious admiration from the top flight. According to the Evening Standard, West Ham, Brentford, and Crystal Palace are all weighing up January bids for the 23-year-old, with the Hammers thought to be the most advanced in their plot to prise him away from the Stadium of Light. There is talk of a potential £20 million agreement, and - worryingly for Sunderland supporters - that talk is refusing to quieten down.

The Standard go on to suggest that as many as five Premier League clubs are interested in the wide man, and the feeling on Wearside is that if the Black Cats can somehow hang on to him this month, they might not be able to for much longer beyond that. Jack Clarke is, in short, a Premier League footballer - it just remains to be seen how and when he actually becomes one.

And lurking in the background to all of this are the winger's former club, Tottenham Hotspur. There has been much subterfuge and intrigue about the exact details of the transfer that took Clarke to Sunderland on a permanent basis in July of last year.

Initially, there were unsubstantiated claims that the attached fee was somewhat exorbitant - or, at least, exorbitant by the typical standards of a side newly promoted from League One. Alas, as time has passed and the dust has settled, those hysterical estimations have dimmed considerably, and now it would appear that, courtesy of Football.London journalist Alasdair Gold, the exact figures have been revealed.

According to Gold, Clarke cost Sunderland just £750,000, but crucially, Spurs managed to secure themselves a sell-on clause worth as much as 25% of any future transfer fees received by the Black Cats. That means that if the attacker were to be sold for £20 million this month, Ange Postecoglou's men would be due a lump sum of around £5 million. If Sunderland hold out and secure a figure closer to, say, £25 million, Spurs could be in line for a pay out of approximately £6.25 million.

Maybe it will happen before the close of the current window, or maybe it will happen in the summer. Maybe Clarke will be sold for £20 million, or maybe he will be sold for a significant amount more than that. Either way, Spurs will no doubt have one eye on the situation as it develops, and will be quietly hoping that West Ham, or indeed, any of the winger's other suitors, can get a deal over the line.