Shares in Grafton Group fell in early trading in London on Wednesday as the builders' merchant and DIY retailer is set to be relegated from one of Europe's most widely followed equity indices, following a decline in its value since the Brexit referendum.

The Irish group, which was added to the Stoxx Europe 600 index early last year, is set to lose its position on December 19th, stock market index company Stoxx Ltd in Zurich said late on Tuesday.

Fund managers whose investments track the key index will have to sell Grafton shares in the interim.

Eight companies, including Dutch insurer Delta Lloyd and German energy company Innogy, are set to join the index on the same day, replacing groups including Air France, UK housebuilder Bovis Homes and Grafton.

Grafton's shares fell by as much 1.7 per cent on Wednesday to £5.77 (€6.73). The company has lost about 18 per cent of its value since Britons voted in June to exit the European Union.