Four have tried, and four have failed. First came a towering Togolese, followed by a stocky Dutchman sandwiched between two misfiring Spaniards. If supporters are ever required to provide an embodiment of the idiom “poisoned chalice”, they need only namecheck Emmanuel Adebayor, Roberto Soldado, Vincent Janssen and Fernando Llorente in the same sentence — those who have borne the “Harry Kane understudy” placard. The first pair did so unwittingly; the latter well-enlightened to the fact. The clock is ticking; transfer deadline day approaches. But in his latest Q&A with the British press, Mauricio Pochettino has extinguished any hope of incomings — nothing new there, eh? — and confirmed outgoings are the only real possibility. Vincent Janssen will surely be one of the expected departures; Fernando Llorente would have been too had Tottenham’s key man not found himself on the treatment table. And it’s since 2014, when he first burst onto the scene, that this Boy Wonder has afforded his club one paradoxical problem: how do acquire a worthy replacement for a player who is indisputably irreplaceable? That’s not to say Spurs haven’t tried. Their last two attempts have seen them purchase two strikers of contrasting breeds. If the short, scurrying Janssen played the part of stray Jack Russell easily tamed by opposing defenders, Llorente is the frail, retired Greyhound haunted by past defeats on the racetrack. Neither have been convincing when given the lead. And as Janssen departs, soon to be followed by Llorente (when the time is right), Tottenham should finally put paid to their pursuit for a Kane back-up. As to obtain a striker who could mimic even the most microscopic effect Kane has on this team is near-on impossible. There’s a reason why Chelsea (Hazard), Barcelona (Messi) and Juventus (Ronaldo) are not in the market for back-up for their star player, despite riches available. As well as these players being one-of-a-kind, they, like Kane, are so intrinsic to their side’s attacking identity that to seek a like-for-like would only result in the purchase of a knock-off version doomed not to live up to the real thing. Of course, fans are quite right when they declare spending signals ambition, but to spend big bucks on a back-up striker for Kane — such as the £50m mooted for German wunderkind Timo Werner — would see the club reenact the KLF’s actions on Jura in 1994. More than any other position in football, strikers require a consistent run in the starting XI to find form. Even when Kane is only half-fit this is never going to be feasible. This is why “super sub” strikers in the Premier League — Solskjær, Hernandez, Giroud, Sturridge, Defoe — are romanticised over so copiously. They’re a rarity. And even if Spurs were to find a forward in this very mould, the player would be expected to be indefatigable as well as having an aptness in making the net bulge. Strikers at Spurs are the first player to action the Pochettino high-press; if the forward is leaden-footed — à la Llorente — the team does battle with its attack blunted. Should Spurs fans worry, then? The return of Son Heung-min will provide a stern rebuff to that suggestion. The attacker’s mix of assured finishing and blistering speed makes him the consummate Harry Kane “replacement” — as evidenced away at Chelsea and Bournemouth last season. It’s unfortunate then that Son’s nationality sees him miss matches for Spurs even when he’s fit and firing. If this wasn’t the case then perhaps talk of acquiring a Kane back-up would be no more than a whisper, especially when the club are in desperate need of a first-rate central midfielder and fresh full-backs. That, unlike a second striker, should be Spurs’ top priority in the transfer market.