The English hop is apparently under threat with one hop merchant warning "If we don't stick up for the UK hop industry now, there will be no industry in a decade's time." According to the hop growers, imported foreign hops from the Czech Republic and United States are driving the English hop to the point of extinction.
In the early 1970's, Christopher Hutt in The Death of the English Pub predicted that Britain's entry into Europe would lead to a ban on the English male hop and an end to the brewing of bitter. That hasn't happened and I doubt that the Kent hopfields are going to disppear now either. Brewers have been importing Czech and US hops and using them along with English ones since at least the nineteenth century. As the the head brewer at Kent's biggest brewery Shepherd Neame says "We are hugely committed to Kentish hops for a variety of reasons. With such an abundance of great hops on our doorstep it doesn't really make sense for us to buy hops from elsewhere."