For Scottish shortbread maker, sterling crunch pushes up Brexit costs

* Sterling down 17 percent since Brexit vote

* Costs soar for Scottish shortbread maker

* Brexit uncertainty bites for some companies

* Prices could rise as costs rise

By Elisabeth O'Leary

HUNTLY, Scotland, Oct 8 (Reuters) - Sterling's plunge since Britain voted to leave the European Union has pushed up costs so much for Scottish shortbread maker Bill Dean that he may have to lift prices to balance the books.

Already Dean, who employs 150 people at his factory in the rural northeastern county of Aberdeenshire, has a 3 million pound ($3.7 million) investment plan on hold and says he may eventually have to shrink his business - and his workforce - if costs keep rising.

Dean's family business, born in his mother's kitchen in the 1970s, imports the chief ingredients of the rich traditional Scottish biscuit: butter, flour and sugar. However, only eight percent of his sales are abroad, so for him the weak pound brings few benefits and a lot of headaches.

Sterling's 17 percent dive against both the dollar and euro since Britons opted for "Brexit" on June 23 - signalling a break with more than 40 years of stable trade within Europe - has come on top of another problem that is eroding profitability for the factory in his home town of Huntly.

Prices for butter - and shortbread needs a lot of it - have jumped 75 percent since the referendum, inflated not only by the weak pound but also by volatile prices of its raw material, milk, on European commodity markets.

"After a while with higher costs and haemorrhaging cash to keep up, your margin gets eaten away and your (profit) has taken a pasting," Dean, who turns 52 on Monday, told Reuters.

"No business is capable of absorbing those kind of price increases for any length of time," Dean said at his factory. "We'd be looking at a reduced business model with fewer people if this cost trend continues in the coming years."

Brexit may well push up prices for British shoppers, and it has already cast doubt on job prospects. At the other end of the corporate scale from Dean, Japanese giant Nissan has said it may scrap potential investment in Britain's biggest car plant unless the government compensates it for any new tax barriers erected post-Brexit by the EU.

However, some British-based businesses will benefit from the weaker pound, which makes their exports more competitive - as long as they still have tariff-free access to the single European market.

The FTSE 100 stock index, which comprises the biggest London-listed corporations, has soared 20 percent since referendum day to near record levels. Overall, these groups earn the bulk of their money abroad, so the currency slide raises the profits that they report in sterling.