Rationale for long term GBP weakness
USD to remain strong long term - Tariffs on imports in the US will increase inflation - Fed may have to slow down interest rate cuts.
UK economy showing no signs of recovery - at best growth is forecast at 1.5% which is still 'optimistic'. Rates may drop quicker than the US over the next 6-12 months further heaping pressure on the Pound - looks like will revert to mean and approx fair value of 1.25 before the next long term move.