Held at “readiness” against whom?
The invasion of the Spanish British retirees outraged over losing all of their "free stuff"
That’s my question. 3500 is not a large number and I cannot imagine having a military conflict outside of the UK border over this. Must be to augment police within the UK as there will be globalist lefties much like our own that will take to the streets. But that’s a guess.
Not necessarily ‘against’ anybody. it’s more likely to be to support the civil authorities in the event of any breakdown of essential services, temporary or otherwise - as already occasionally happens when the military are called in for support in civil emergencies.