It is easy to miss the single sheet of A4 paper, with a pale blue logo and dulled gold lettering, that hangs above a sideboard in the spacious hallway, unobtrusive among the more eyecatching ornaments, portraits, photographs and yards of books. The letter is from the municipality of Anzio on Italy’s Mediterranean coast, thanking Denis Healey for his role in planning the amphibious landing that liberated the city from Nazi control in 1944. That was a year before Healey first stood for parliament and 48 years before he left the Commons to become Baron Healey of Riddlesden, having served as defence secretary and chancellor in Labour governments of the 1960s and 1970s and as deputy leader of the party in the vicious early years of 1980s opposition. Healey entered politics to defeat fascism and left after communism crumbled. Yet this letter is the only memento of the 20th century’s ideological strife that I can see in his grand home in rural Sussex.

“Anzio was a piece of cake,” he says when he catches me mulling the document. “We had total security. We captured some of the German officers in their pyjamas.”

There isn’t a hint of bragging in the voice, which carries only a faint quaver betraying 95 years of use. The landing at the Porto di Santa Venere in 1943 was “a different story”. The plans went awry and the Allies were pinned on the beach under mortar fire, taking heavy casualties. “We had to sleep between concrete blocks on the beach,” Healey reminisces, but then abruptly changes the subject: “Do you want me to take my clothes off?”

This ribald provocation is addressed to the photographer, who has set up his equipment for a portrait as we have been talking. Healey has been a keen photographer since childhood and the lens brings on an attack of boyish mischief. He grins and gurns with impish vigour. It seems quite plausible he would, if asked, strip naked. After the shoot he whips out a small camera from the pocket of his beige corduroy trousers and insists on shooting us right back. A brief anecdote rolls out about the time he met Henri Cartier-Bresson. This time there is a definite hint of bragging.

The arts, Healey says, have sustained him in retirement. It is, in a sense, a return to a first love. As an undergraduate at Oxford, he was a voracious reader and occasional writer of poetry, but the imperative of defeating Hitler intervened. A communist at university, he entered the army in 1940. “So many young middle-class boys and girls in my generation joined the Communist Party because it was the only unequivocal anti-fascist party,” he says of the late 1930s, when Neville Chamberlain’s appeasement policy was still the orthodoxy. “The Labour Party was half pacifist in those days.” He switched to Labour in 1940.

It wasn’t just the urgency of the cause that left its mark on Healey’s politics. The postwar generation of politicians, he says, was shaped by the galvanising force of collective military endeavour. “The great thing about serving in the army, whatever your party, was that it taught you the importance of inter dependence,” he says. “And the importance of planning and of knowing that planning will go wrong.”

It was in the 1970s, when Healey was on the economic front line as chancellor, grappling with inflation, fiscal crisis, soaring oil prices and industrial strife, that the 1945 spirit of planned progress unravelled. Looking back now, did he sense the scale of the cultural and political change that Margaret Thatcher’s victory heralded in 1979? “I expected her to move in that direction. I never expected her to do so much.” He was advised early on to watch out for the up-and-coming Thatcher by an MP friend who knew her well. “He said, ‘She’s good-looking but she’s also politically brilliant.’ He was right.”

There is no partisan animus in Healey at all, whether with regard to past battles between the parties or to his own bruising combat with Labour’s hard left.

“In those days the unions had far too much influence. They could really veto anything they didn’t like,” he says, skimming over one of the most turbulent chapters in his party’s history as casually as he sips his coffee. “And that time has gone.”

Healey seems uninterested in the miniature daily dramas of politics, looking only at the broad sweep. It is the perspective of a man resting comfortably on the shore, having swum through much rougher historical tides. “The big change is that the class system has totally disappeared. When I started out in politics, working-class people wore cloth caps, middle-class people wore trilbies or occasionally bowler hats and, of course, the toffs wore top hats . . . If you ask people what class they belong to they say, ‘Don’t be silly – I left school years ago.’”

Doesn’t the current cabinet, stuffed with wealthy public school boys, suggest there is a stubborn endurance of an old class hierarchy? “Maybe up to a point,” he concedes. “But only inside the Tory party.”

It was Healey’s late wife, Edna, who coined the term “hinterland” as a metaphor to describe the depth of experience, interest and character that give substance to some political figures and whose absence limits others. It is, he says, a rare trait nowadays: “None of them have that in either party. In my time, people didn’t start earning money until well into their life in politics. Now people can get a career out of politics as soon as they leave university. They don’t have experience of the real world.”

That could well be said of Ed Miliband, I note. Healey is more generous in his own appraisal of the present Labour leader. “He’s doing very well, actually,” he says. “His only disadvantage is that he doesn’t have the charisma of his brother, David. But he doesn’t upset people.”

Is there anyone who impresses in the government? “No, not really, except on the Liberal side. [Vince] Cable is a very able chap, [Nick] Clegg is able, I think.” However, Healey doubts that coalition with the Tories is sustainable for the Liberal Democrats. “My own opinion is that the Liberals in the country will force the leaders to leave the government before the election.”

Labour's big beast says he doesn't "care enough" about British politics. Portrait by Kalpesh Lathigra

Healey is kind to David Cameron, describing him as “the first real Tory leader since Thatcher”, but confesses that his interest in domestic matters is dwindling. He chooses instead to stay more abreast of foreign affairs. “I’m particularly interested and excited that China is obviously going to overtake America before too long both in military and economic strength.” (This observation is followed by an anecdote about a late-night tête-à-tête in 1972 with his “very great friend” Zhou Enlai, Chairman Mao’s moderating premier.)

On European matters, Healey is a sceptic, “mainly because of the importance of the Olive Line”. He clarifies: “North of the line where olives grow people pay their taxes and control their spending; south of it, they don’t and they get very heavily into debt . . . That division makes federation impossible – inconceivable, in my opinion.”

In a referendum on membership of the European Union he would vote to leave. What, I wonder, does he make of the UK Independence Party? “I think they’re bastards. But, like the fascists did at one time, they can start to shift politics.”

Is Nigel Farage a dangerous demagogue in the making? “I don’t see enough about politics now, or care enough, but Farage seems to me to have a very effective personality, which will hurt the Tories.”

That remark about not caring about politics is a gentle rebuke to my line of inquiry. There is plenty more I’d like to ask. It isn’t every day you get to sit down with someone whose career spanned every domestic and international drama from D-Day to the fall of the Berlin Wall. Yet the difference in Healey’s demeanour when released from political topics is extraordinary.

The mention of poetry causes his eyes to brighten beneath those unruly brows that were such a gift to cartoonists. “I quite like Betjeman because he is good at suburban life.” A rhapsodic tone banishes the quaver from his voice. “But there’s nobody to touch Dylan Thomas!” It feels suddenly as if the struggles of the 20th century were a digression – exciting, important, but necessarily conducted in prose, when all along Denis Healey was craving the company of poets.