Although conversion from dollars to sterling is the inverse of from sterling to dollars, these charts use the first, to make comparisons easier, at least for myself. Going back to the example, at the end of 1986, the UK equity fund was £9,769 and US equity fund was $11,787. Parity (breakeven) would have needed an exchange rate of 1.21 rather than the actual 1.51.

The charts show the actual initial rate (blue), the parity end rate (red) and the actual end rate (grey). Where grey is higher than red, the currency impact was negative. For equities, the impact was more or less 50:50 but it was highly negative for bonds.