By Jack Mendel Founder of beer chain Brewdog has warned Britain’s political system faces an “existential crisis”, and has offered a solution to get on top of it. James Watt took to LinkedIn to vent his frustration at the levels of debt being serviced in the UK economy at the moment, which makes it “impossible for us to get our governing system back into balance”. He warned unless something changes very soon, it would lead to the “self-destruction” of the governing system. Watt, who quit as head of Brewdog in May after 17 years at the helm, has long been a critic of the Conservative government’…