Why, when there's ample capacity in Europe?
Or is it just about having "British" stamped on them?
Perhaps you must have missed the contractual tug of war that took place over vaccine procurement at the end of last year.
The ability to produce important products not only provides security of supply to ourselves but can also give us the means to assist our friends overseas, which is useful diplomatically.
Or you could just go to sleep and hope that the international free market will rescue you when you're in a tight spot.