The race has been held since NUMBER@1 -LRB- see list of LOCATION@1 Cup winners -RRB- and was originally held over two miles -LRB- about NUMBER@2 metres -RRB- but following preparation for LOCATION@2 's adoption of the metric system in the NUMBER@3 , the current race distance of NUMBER@4 metres was established in NUMBER@5 .

The race was first held over two miles , about NUMBER@2 metres , but after LOCATION@2 changed to the metric system in NUMBER@5 it was changed to NUMBER@4 metres .
