Roy Keane may have orchestrated the final sundering of his relationship with Alex Ferguson, and by extension Manchester United. There were suggestions that his criticism of team-mates following the Middlesbrough match may have been deliberate to facilitate a speedy departure in the January transfer window.

In the past Ferguson has loaded the gun and used Keane to fire the bullets but it seems their relationship had broken down irrevocably. From being so close the relationship has gone to the other extreme. One thing that's assured is Keane's departure has started the egg timer on Ferguson's own time at Old Trafford.

The United boss is unlikely to survive too much longer unless there is a massive reversal in fortunes. You can expect the chants of 'Keano' to ring out loud and clear at the Valley when United play Charlton today. The die-hard United fans revered him as a player and it is those same supporters who travel to away matches who will make sure his name is not forgotten.

United have spent the past 18 months trying to replace him and but for Chelsea's financial muscle might have succeeded by securing Michael Essien's signature. If they had landed him then Keane would have departed on amicable terms, gently fading into the background and everyone would have been on the best of terms. The king is dead, long live the king.

Now it looks, despite the public utterances, like an acrimonious split.

Keane has never placed great store in the friendship of team-mates off the pitch but on it he commanded huge respect even if they didn't like him as a person. He was very good at manipulating situations and was a shrewd judge on most occasions: the obvious aberration being the World Cup and Saipan when he just didn't seem to want to be there.

If he was slightly older in years, he'd probably be viewed as an eccentric.

In his pomp he was rarely heard from off the pitch but as his powers have waned so quirkiness has grown. In the past on the rare occasions when he granted interviews, he was reasoned and articulate and his words carried resonance. He was hugely respected.

As injuries began to take their toll and the abilities he had shown in his youth, the dynamism and athleticism declined, then his outbursts were a little more frequent. One of his best performances in recent times was that night at Highbury when there was a flash of the Keane of old; stalking the tunnel with intent and laying down the marker for what ensued.

United won 4-1 and Keane was in his element. It is the night in Turin though that he'll perhaps be most fondly remembered for at Old Trafford. His performance was quite simply sensational as he hauled a United team back from a 2-0 deficit and took them into the Champions League final in which eh would play no part because of a booking.

It was a selfless performance and a graphic illustration of why he was so respected by his team-mates on the pitch. He dominated a Juventus team of great quality and ability and he nudged United closer to the Holy Grail of Champions League success. At times it must have been difficult because he was capable of such extraordinary highs to be followed by depressing lows: Saipan, Alf Inge Haaland to name but two.

He had a fantastic effect on a dressingroom, particularly on the young players, and whether you liked him or not, you'd always be better off when he took the pitch. He was a superb player for both United and the Republic of Ireland and that is how he'll be remembered by the majority of supporters.

As to where he'll go now? The smart money has been on Celtic for some time. There have been overtures in recent months and all at Parkhead would welcome his arrival. Dermot Desmond is a big fan while Gordon Strachan is smart enough to realise the impact he would have for the club on and off the pitch.

Keane is not quite finished as a player - he'll probably soldier on for another 18 months - and then try his hand at management.