David Cameron invited French President Francois Hollande to half a pint of ale and posh pub food at his local - but the pair toasted a defence and nuclear entente with French wine.
The Prime Minister and Mr Hollande dropped in at The Swan Inn in Swinbrook after announcing a two-year £120 million feasibility study for a new armed drone and joint work on an unmanned counter-mine craft at nearby RAF Brize Norton.
Mr Hollande appeared to enjoy the visit to the boutique Cotswolds gastropub on the banks of the River Windrush, which has featured in Downton Abbey and belongs to the last surviving Mitford sister.
The pair enjoyed locally-sourced potted shrimps, rainbow trout and Bramley apple and raisin crumble.
But despite announcing a new defence deal, it remained in doubt whether they had reached any agreement on which country has the best food.
Landlord Archie Orr-Ewing, who is the heir-apparent to the Orr-Ewing of Hendon baronetcy, said that while the Prime Minister had visited a few times, it was the first time he had hosted a president.
He said: "They were a bit short on time - we managed to serve a couple of half pints of Hook Norton, our local brewery, at the table but there wasn't time for pork scratchings at the bar.
"It wasn't really a boozy occasion and it wasn't really about wine anyway, it was more about the food. We gave them our normal menu and those were the dishes they selected.
"We are honoured that they chose our establishment to do business."
Established in 1885, The Swan featured as a set for Lady Sybil's elopement with the family chauffeur on hit ITV show Downton Abbey.
The pub, which is also a favourite haunt of top model Kate Moss, is owned Deborah Cavendish, the Dowager Duchess of Devonshire
Today's visit is not the first time that a British prime minister has hosted a foreign visitor at the pub in recent years.
In November 2003, a £1 million security operation had to be put in place when Tony Blair invited US president George Bush to the Dun Cow pub in Sedgefield, County Durham.
British officials said the two leaders sampled ale from the local Hook Norton Brewery at the pub, but accompanied the meal with French red and white wine.
The 90-minute working lunch at The Swan was dominated by issues of EU reform.
The leaders discussed how free movement and the welfare system worked, following Mr Cameron's complaints about foreign workers in the UK claiming child benefit for their families at home in other EU countries.
A British official said: "There was certainly some agreement that there needs to be more done in terms of social security."
The 2017 timetable set out by the Prime Minister was also discussed.
"Timing came up, with a focus on the timetable that the Prime Minister set out," the source said.