Of a particular white Burgundy, the committee wrote: October 2008: "Slightly soapy odd palate - hope it comes round. Review in 2011"

February 2011: "Not soapy, but harsh acidity"

May 2011 (when the state visit took place): "Used on US State Visit - feedback from Palace"

Wine marred by "harsh acidity" and once deemed "soapy" was served during a US state visit, the tasting notes of the government's wine committee reveal.

The committee also says its cellar's finest Armagnac is best reserved for "use with European guests".

Its five tasters - all volunteers - advise of one wine: "Use with extreme caution for heads of state - fabulous!"

The wine committee provides advice on which wines from the state collection to keep and which to drink.

Its newly published report demonstrates a passion for public service.

"Sensational," the committee declares of the Chateau Latour 1990, which retails at north of £750 a bottle.

"Powerful, outstanding and wonderful," is its verdict on the Batard-Montrachet 1985 Grand Cru (Domaine JN Gagnard). "Consider keeping it for very special occasions only."

Thatcher's palate

But the state oenophiles have had to make some tough choices recently. Lesser vintages are described as "remarkable for the price" and "austerity wine".

Although the Le Pin 1986 is judged to be "delicious and scented, at its best" in March 2012, they recommend: "Sell the majority, if not all." The government has since parted with 36 bottles, contributing towards a return of £44,000 from wine sold in 2011/12.

The government's aim is to buy promising vintages "young and relatively inexpensively", before storing them in the government hospitality wine cellar, located near to Buckingham Palace in the basement of Lancaster House.

The cellar revealed In pictures: The government's wine cellar

The cellar's contents cost £850,000 and are now worth an estimated £2.95m.

While the wine committee's analysis is clearly hard-headed, there is some evidence that it is not entirely immune to external political pressures.

"Described on various occasions by French delegations as a national treasure," the committee notes of the Corton 1961 Grand Cru, Cote de Beaune, Bouchard Père et Fils - soon to become the recommended tipple for visiting heads of state.

"The prime minister called it silky," it reveals of Baroness Thatcher's enjoyment in 1989 of the Chateau Margaux 1961 - which was subsequently bumped up from an A rating to an A1.

'Write off'

The report often recommends of its preferred bottles "use with an appreciative audience" or "special occasions only".

The 1931 Quinta do Noval port - "sublime - the best this century" - is recommended for "very special occasions only". The government and its guests polished off three bottles in 2011-12, although they have not disclosed when or where.

But the public sector wine buffs are not shy of expressing the odd dim view too.

"Slightly soapy odd palate - hope it comes round," they remark of a particular white Burgundy in 2008. By 2011, the wine was: "Not soapy" but suffered from "harsh acidity".

Despite this less-than-resounding praise, the wine was apparently served at Buckingham Palace as US President Barack Obama and his coterie paid a visit to the Queen.

We may never know what the committee made of an Italian red procured specifically for Italy's state visit in 2005: its comments have been redacted, perhaps for diplomatic reasons.

But another drop inspires a fuller narrative, tinged with tragedy.

"Very curious, odd and disappointing - check with merchant," laments the committee in 2006.

"Still odd, slightly asparagus nose - return to merchant," it adds in 2009.

Finally, it concludes in 2011: "STOCK WRITE OFF."