Annual growth in London watch sales fell behind the rest of Great Britain in July for the first time in a year.
The total value of watch sales in London rose by 3.1% in July compared to a year ago, while growth for the rest of the country was 5.3%.
July data is the first that can be compared to a full month of retail sales data in the post-Brexit era triggered by the vote in June last year.
Since that time, the drop in the value of the pound made watches over 25% cheaper than the same watches bought in their home markets for foreign visitors. But watch brands have closed that price differential over the past year with a series of price rises.
GfK says that the average sale price for every watch sold in Great Britain has risen by 15.1% since July last year.
Total sales by volume of watches priced at over £1000 has risen by 11.6% since July last year, virtually in line with the 11.8% rise in the total value of sales.
The value end of the market continues to decline, with total sales of watches priced at under £500 falling by over 6% compared to July last year.
For the full year from August 2016 to July 2017, the total value of sales of sub-£500 watches has declined by over 25% over the preceding year.
Luxury watches costing more than £1000 have seen the total value of sales increase by 27% in the same year-on-year comparison.