Diageo's 18-year Old Parr Superior blend beat off competition from more highly regarded single malts in Murray's 2007 Whisky Bible. Another Diageo brand, White Horse, won blended whisky of the year.
But the respected judge, who worked through more than 1,000 varieties, used the awards to warn that all scotch whisky distillers were missing a potentially lucrative market for blended whisky at home in the UK.
The oversight may prove important for alcoholic drinks firms like Diageo as they assess how to maintain sales in a UK market predicted to stagnate over the next five years.
Murray said: "To be honest, British drinkers just don't have enough choice when it comes to Scotch. We are going through a golden age for blends right now, but for the majority of drinkers here, you'd never know it."
Both Diageo's Old Parr and Whie Horse award winners are export brands, with core markets in Japan in particular.
"It's time the marketing people - and whisky retailers - were a bit braver and made them as mainstream as the single malts which are flooding the shelves," Murray said.
Single malts, generally made in lower quantities, have become more prestigious than blends in recent decades, but Murray warned blended whiskies should not be so quickly dismissed.
"Theoretically they should be better because you should be able to incorporate many characteristics into the whisky and forge something unique."
His comments came as a new report urged alcoholic drinks firms in the UK to rethink their strategies, in a bid to prevent market share loss in a sector forecast to stagnate over the next five years.
Consumption of alcohol per person would remain flat at 15 litres per year in the UK up to 2010, while expenditure would only rise 0.9 per cent - well below inflation - according to estimates from market research group Datamonitor.
Spirits is one category analysts expect to lead growth over the next few years.
A spokesperson for the Scotch Whisky Association denied whisky producers were neglecting the UK market. "The home market is vitally important to distillers and consumers can enjoy a great selection of both malt and blended Scotch whiskies."
He said Britain was the second largest market for bottled, blended Scotch whisky, accounting for a tenth of global sales, or 96m bottles, per year.