TIME to take stock. The weekend's business took me to Clones, that footballing megapolis of the north. Dramatic business it was. Before the match, it was all a bit like one of those films, Under Fire or Salvador. Moving the car slowly through the crowds, fleeing up the hill from the fast food stalls, I had to make my way past barriers guarded by mend in uniform.

Trailing press cards and white flags out the window to assure the natives of the occupants' intentions ("southern media, we mean no harm, we want to tell your side of the story"), the car is pulled up just a couple of checkpoints from the destination. No car pass? Didn't know one was needed. Crisis.

Passengers begin pooling hard currency, peeling off designer tee shirts ("here, use this as a tent for your family") but we're waved through and soon slide down the laneway into the car park behind the Arthurs Stand and pull up between two of those big, expensive cars with northern registrations.

Clones. Something always happens here. The air is heavy with expectation but the more laconic strain of Ulster person bears up to it with characteristic calm. Once at an Ulster final a good while ago, there was a minute's silence for a clergyman who had passed away before the match got under way. "Ah," says one of my local companions, distinctly unfazed, "there's always a priest drops dead in Clones the day of the Ulster final.".

Sunday's requiem was for Derry. The brilliance with which Tyrone's game plan was conceived and executed might obscure the significance but it was the last we are likely to see of a team that, almost completely unchanged, has been the most consistently feared this decade.

It ended its journey as it began as Eamonn Coleman's team. Two managers have been in charge since Coleman was dumped two years ago but the side that he led to the All Ireland in 1993 was, with minimal variation, the one which started against Tyrone at the weekend.

Derry's record speaks for itself. With four national titles since 1992 (no county has won more this decade), they have been a model of consistency. Four times in the last five years, they have either won the All Ireland or lost narrowly to the team that did and after Sunday, you'd say that Tyrone are most capable of turning that statistic into five out of six.

Two maxims governed the match. The first of these is the watertight old boxing saw - "they never come back." Once a team begins to slide in other words, does appreciably worse in a championship than in the previous year - there is little chance that it will regain the higher level unless fundamentally altered.

Two examples illustrate the need for change, Dublin and Down.

The Dublin side that lost the 1992 All Ireland final was similar to that which had played the four match series against Meath a year before. By the time they lost the 1993 semi final to Derry, the team had changed to the extent that it had a completely new full back line and a changed centrefield. From that starting point, it went on eventually to win an All Ireland.

Down are a more straightforward case. There were significant changes between the 91 and 94 teams - in between which the county had suffered dreadfully demoralising defeats to Derry. Into the side came Mickey Magill, Brian Burns and, most importantly, Greg McCartan. The management also moved around key personnel - Barry Breen and Conor Deegan to name just two - to such effect that the team discovered spectacular new momentum.

Against such precedent, all Derry mustered on Sunday was one new face (among players rather than management which has certainly registered the dynamic of change) from the team that won the All Ireland three years ago Sean Lockhart, a talent certainly but one whose time is in the future - and wing back Johnny McGurk's re deployment to wing forward never had the desired effect.

THE second maxim, "never trust the League," is one of the most popularly ignored injunctions in football. Despite the pressing evidence to the contrary (no county this decade has won the League and championship in the same year), each May people throw up their arms and bow low at the altar of the new league winners.

Derry should be particularly aware of this as, in the light of the weekend, their three League wins have been followed by championship catastrophe. In 1992 when their powerful presence was first felt, it was easy to believe that when winning the League, they had no regard for the rules. But the rules caught up with them in that year's Ulster final.

In the interests of accuracy, I should disclose that I am on broadcast record - a week after this year's League final - as expecting a Cork Derry All Ireland final (a prediction I repented, publicly, before last Sunday).

Were I to be accosted one night by someone, who had seen this programme (impossible as anyone up watching Channel 4 at eight o'clock on a Saturday morning is probably locked in chains during the hours of moonlight), my reply would be that the championship is an organic thing that grows and develops as the summer progresses, that we must act on the evidence of the moment.

Derry's defeat is also another blow to the convention of teams being "caught on the hop": a favoured team that loses unluckily or bizarrely one year will set matters straight the next. Again, there is ample case history on this.

Cork had hardly won the 1989 All Ireland before people were saying that Meath would win the following year. This was because the latter, as All Ireland champions in pursuit of three in a row, had been surprised by Dublin in that year's Leinster final. Dublin lost to Cork; Meath wouldn't have, ran the theory.

Meath and Cork squared up in the 1990 final to test this. Far from crumpling beneath the weight of their unworthy victory 12 months earlier, Cork beat Meath and did it with 14 men. Meath lost the next All Ireland final to Down and haven't been out of Leinster since.

Cork were to suffer the same fate. Narrowly beaten by Kerry as they chased a third All Ireland, the team was viewed as bankers to return the next year. As the time wore on, the assumptions became less convincing and when the counties played in Cork in May 92, Kerry won this time by 10 points.

Similarly, Tyrone's merits were disregarded because last year's win over Derry was in such freakish circumstances. Instead of being able to exert revenge two days ago, Derry were just more comprehensively beaten.

So, Derry's defeat fitted an established pattern but as patterns carry so few guarantees in sport, it was generally unforeseen. Let everyone be more wary the next time.