Oh do keep up old chap. Mr Dow said...
Because it was not designed for this task the Tornado necessarily takes much longer to get airborne from alert and has a very poor mission reliability, with many planned missions cancelled every month. This has resulted in the US Air Force having to step in, to ensure that our troops get the support where and when it is needed.
Hence the answer...
PS. The Tornado was designed for Nuclear QRA and so sitting GCAS is something it is very well suited to!