I don;t understand your point. GB can set their tariffs as low as they want or have none at all. That's up to them.
Also lower currency evaluations raises exports which should be good for GB workers.
Tell me about lower values of the pound. Tell it to all those "GB workers" off on holiday to other European countries. Tell it to your British credit card next time you visit the supermarket for your weekly shopping.
Think about it when your next trip abroad to Europe includes buying travel insurance you once did perfectly well without, the serious stuff once yours for the asking anywhere in the member countries, be they down on the Costas or up in the Alps.
Be grateful the next time a factory closes because your leaders have decided that having joint production ventures with other European countries wasn't worth keeping; you can always claim unemployment benefits, can't you?
I won't even mention the plight of us old sods living abroad, caught in a mess not of our own making, and upon which we could not vote, pensions rendered even lower than they were to begin with (to get an idea ot relativity: France is trying to establish a single pensions system to rationalise the many different ones that currently complictate life there; the suggested, common level, is almost double what I get from her Majesty's gracious government.) You get an idea of who the poor relations within Europe
already are?
Lower the value of the pound, and you at once make it even less attractive for all those highly skilled Spanish (and others) nurses and doctors to consider facing a working life in a grim Britain, once a reasonable trade because of the slightly higher salaries and value of the pound against both the local salaries and the euro currency. Recruitment has already tumbled.
Yeah, as Harold Wilson said to international laughter: devaluation doesn't mean that the pound in your pocket is worth less...
(Jeez, I currently feel betrayed by my own erstwhile party of choice, but thinking back to the lunatics on the left, as dear Harold & Co., makes me even more desperate; perhaps the Libs may now come back with a reformed programme and set of realistic aims - they wiped the floor with the Conservatives yesterday at a local election, as the only anti-Brexit party on offer. There may be a silver lining behind that twister after all!)