This is not easy, since most sell tobacco, gold, roses and other goods that can be observed and recorded as they leave the country.

ECONOMIST: Zimbabwe��s beans and bicycles

Peter Beales Roses claimed its 19th Royal Horticultural Society gold medal at last year's Chelsea Flower Show, where the nursery revealed three new roses at the show, including the Queen's Jubilee Rose.

BBC: Peter Beales: RHS Chelsea gold-winning rose grower dies

Mr Beales dedicated his life to roses, breeding varieties for the Queen, the Queen Mother and Prince Charles, and winning 19 Gold medals at the Chelsea Flower Show.

BBC: Peter Beales