Greater China has put a dampener on the otherwise stellar success story of revamped luxury brand Burberry.

The company had earlier posted an 11 per cent rise in revenue to £2.5 billion and a seven per cent increase in pre-tax profit to £456 million in the year to March.

But on Friday is warned that a favourable fluctuation in currency would boost its bottom line by £50 million would actually only in fact deliver £10 million, thanks to a rise in value of the pound against the Hong Kong and US dollars.

Investors were spooked, perhaps more by the scale of a financial miscalculation which was somehow out by £40 million in just 11 days as by any concern over the value or performance of the brand as a whole. Shares shed six per cent of their value in the day’s trading.

Last year’s pro-democracy protests in Hong Kong, along with the much-publicised shift in the demographic of mainland Chinese tourists hit Burberry hard, given the territory accounts for 10 per cent of its global sales.

So a sales drop in Hong Kong measured in the mid single digits can easily impact the bottom line. So, too, wallet-tightening in China’s mainland. So while Burberry had expected some cushioning from favourable exchange rate trends, further analysis since has apparently revealed less positive trends.

The weakening of the euro has increased what luxury brands refer to as ‘grey market sales’, where stock is bought from wholesalers or stores in Europe for sale at a profit in China and Southeast Asian markets. This prompted the brand to increase Europe prices, and reduce them in Asia, affecting revenue at both ends, but protecting the integrity of its supply chain.

One dealer observed that lowering the 2016 guidance had hurt Burberry, hinting the share price impact was an unfair judgment.

“Underneath, the numbers read well and are ahead of forecasts and the company is doing a lot to make the business sustainable,” one London dealer told UK news media.