There finally seems to be a degree of momentum building in a January window that has for the most part been a tepid affair. A month dominated by loans, swaps and minor deals; everything looks set to change as the biggest Premier League clubs join the festivities in the final few days.

Chelsea and Manchester United look set to battle it out as the window's biggest spenders, with both clubs looking to build the foundations for a successful new era. Chelsea have already tied up deals for Nemanja Matic and Mohamed Salah, but with United perhaps still doing the standout bit of business with a £37.1m club record transfer to bring in Juan Mata.

The exciting thing going into the final few days is that neither club looks ready to lay down the cheque book, and with intent already signalled there could yet be another flurry of transfer activity.

Attention now seems to have firmly shifted to the future of precocious young left back Luke Shaw. The 18-year-old Southampton wonderkid has adapted to Premier League life with consummate ease, and is already showing the kind of maturity that vindicates the high hopes many have for him going forward.

World-class wing-backs are few and far between in the world game, and this is exactly why such a hefty price tag has been put on Shaw. Interest is so high that the young Englishman could be allowed to leave for us much as £30m, a seemingly extortionate amount of money for a man of his age.

Both clubs are in the market for a left back, and seem intent on getting their man, but who represents the better move?

Chelsea and United have similar problems; they have ageing left backs without the necessary replacement being brought through in the meantime. Chelsea have experimented with Bertrand, Azpilicueta and Ivanovic as a replacement to Cole but have never found the right man. United by contrast have persevered with Evra but even now the signs of age are beginning to become a burden.

With news just today that Leighton Baines has signed a new contract at Everton, expect a desperate bidding war to start between two clubs with a notoriously frosty relationship.

The impression so far is that Shaw would slot straight into the first XI at either club, so the better move is less a question of playing time, more a question of club ambition. Both clubs are somewhat transitory but for me the difference in immediate aspirations is stark. United are rebuilding under Moyes, so much so that Champions League football is looking distinctly unlikely and trophy wins the stuff of fantasy. If Shaw were to move to United it would be about long-term projects above all else, whether he truly believes the club has the ambition to rewrite an apparently sinking ship.

Chelsea’s redesign seems less drastic and more aesthetic, under Mourinho they could yet win the title and look set to go into the latter stages of the Champions League. The draw of silverware shouldn’t be underestimated for a youngster like Shaw whose early years have been spent predominantly away from these concerns. The opportunity to win trophies at the age of 18 is a serious pull and one that should push him towards West London

Developmentally I think it is a different question all together; Chelsea have a poor reputation for nurturing young talent, the Matic deal just underlines this. United by contrast have more often than not shown faith and allowed young talent to blossom in time, Ferguson’s era epitomised this and you would hope Moyes would look to go the same way.

The decision for Shaw is more difficult than it would appear; and some believe that playing for his boyhood club Chelsea may swing the deal. Indeed the glamour of a Mourinho-led Chelsea may well sell the youngster in the short term, but I cannot help but think long term a move up North may be the better bet.

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