The reason was to free up funds for "urgent operational requirements". Like the Litening pods on the Tornado/Harrier, Sniper pods, additional Merlins and getting those HC.3 Chinooks back into service. All for the war effort.
Dates:
July 2004: Decision to retire in 2007
26 April 2007: Decision to retire early
30 April 2007: Retirement of last 16 Jaguars
25 May 2007: Disbandment of 6 Sqn, last fly-past of two Jaguars
29 June - 1 July 2007: Jaguar farewell weekend with two on static
October 2007: Original retirement date
It's not really a problem, the decision in 2004 was of more significance for the type. It's sad for the men and women of 6 Sqn though.
Surely some will go the museums and/or already have, but in the article I read it said that they would be transferred to RAF Cosford for use as ground instructional airframes. Also QinetiQ has two flying Jags at Boscombe Down for trials, not sure when they will be retired.
I've always had a soft spot for this little aircraft. I love the RAF two-seaters.