Bringing in immigrant labour merely works around a problem.
It does not solve it, and certainly creates other problems.
We had an existing population which in the past was quite capable of being harnessed to fight off Nazi Germany, and with human resources large enough to fully meet any skill requirements....with proper education and if necessary, re-training.
The fault lies with government and in some cases, trade unions, not with a lazy and/or inflexible home-grown labour force.
