Even today, the perception of Venice as a city only half-rooted in mundane reality owes a great deal to Canaletto (1697-1768), an artist who made his name producing paintings for English tourists visiting Italy in the 18^th century. Recognisable views are subtly altered, the gently improving instincts of the artist shifting the scene almost imperceptibly away from real life, and into the realms of the imagination.

Restoration theatre has the reputation of being a rake’s paradise – all those randy young aristos in hot pursuit of buxom wenches. But even in the depths of 17th-century playwriting, there was room for repentance and regret among the discarded petticoats and ripped bodices. So it is with Stephen Jeffreys’s The Libertine, his now sharply rewritten 1994 play that was also made into a film starring Johnny Depp.

Here be two modestly scaled masterpieces from the 1760s by George Stubbs, highlights of a centuries-old tradition of painting the horses owned by the Dukes of Newcastle and their lateral descendants the Dukes of Portland (the Devonshires are also connected in a grand web of aristocratic marriages). Stubbs was commissioned by the third Duke of Portland (1738-1809), William Cavendish-Bentinck, indisputably one of the grandest in the land: a politician and a multi-billionaire in today’s terms.

Unswervingly confident, relaxed and assured, the élite of the 18^th century are currently arrayed on the walls of the Royal Academy, gazing down at us with the utmost assurance of their unassailable place in the world, bright eyed and dressed to match. The swirls of public reputation are unpredictable: here is a revelation, the art of one of the most successful and highly prized portraitists of his day, Jean-Etienne Liotard (1702-1789), now almost completely unknown except to specialists.

There are moments in this collaboration between performer and theatre impresario Christopher Green and best-selling novelist Sarah Waters, where, rather like with a Stewart Lee stand-up routine, the audience has to make a conscious decision whether they are going to go all the way not so much with the idea presented, but with the mode of presentation. There are times in The Frozen Scream when it feels like the punchline is getting further away rather than closer.

It won’t come as much of a surprise to find that the staff at Tatler are a bit on the posh side – who’d have thought? – but I honestly doubt they’re that much posher than, say, those at The Times, or The Guardian, or that other esteemed people’s champion, the New Statesman. As for the “posh to common” ratio on theartsdesk – without doing an exact head count, I’m not sure we radically break the mould, either. Such is the way the world rock ’n’ rolls in class-ridden Britain. 

Julian Fellowes, now the Conservative peer Lord Fellowes, left behind the fictional world of Gosford Park and Downton Abbey to give us this sumptuous tour of Blenheim Palace. Nor were its surroundings neglected as vista after vista showed us Blenheim’s lavishly landscaped gardens, fountains and columned monument to John Churchill, ^1st Duke of Marlborough, victorious over Louis XIV. It was his military prowess that led to wealth and Blenheim itself, gifted by the grateful nation and thus an early example of government subsidy.

As unavoidable as death and taxes, as inevitable as the rotation of the seasons, Downton Abbey has created the illusion of time-hallowed permanence in a mere four years. It is often asked how long Julian Fellowes can keep up his script-writing heroics (if it was an American show he'd be marshalling a writing team of dozens), but this opener to series five was so playfully deft and thunderously enjoyable that you'd have to conclude that Downton has become Fellowes's personal fountain of youth.

The disappearance of Lord “Lucky” Lucan in 1974 remains one of the most teasing enigmas of recent-ish history. Following the collapse of his marriage and a bitter battle with his wife Veronica for custody of their three children, the gambling addict Lucan is presumed to have battered the children’s nanny to death, attacked his wife, then fled the country by boat from Newhaven. Elvis-like sightings of the disgraced peer have poured in from around the world ever since.

What is the extraordinary, crowd-drawing appeal of a picture collection reunited, for a short time only, with its original surroundings? Well, for a start, this is no modest assembly of old masters, and Houghton Hall's elaborately crafted ensemble rooms constitute no conventional stately home. The feat of remarrying them has been so successful that Houghton Revisited has been extended for another two months, until 24 November.

Clearly following in the rear of fashionable London, most of which seems already to have zipped to north Norfolk to see the wonders, I arrived from King's Lynn last Sunday with fellow hikers from the previous day’s walk for the Norfolk Churches Trust and found we could buy tickets from the man in the car-park kiosk for any slot that afternoon. Do so too, if you encounter a "sold out" online. This really is a once in a lifetime experience. It hasn’t happened for 234 years, and it probably won’t happen again.

In 1779 the original collection assembled half a century earlier by discerning Sir Robert Walpole, Prime Minister to Georges I and II, was sold to Catherine the Great of Russia to pay for the gambling debts of his grandson, the capricious Third Earl of Orford (the otherwise excellent little booklet accompanying the “show” avoids placing the blame altogether). The wholesale delivery - by frigate to St Petersburg that spring - sets the sale apart from previous grand dispersals, like that of Charles I’s goods, by virtue of its concentration in the Hermitage. By no means every picture that’s come back to a temporary roost hails from there; where would Houghton Revisited be, for example, without Velázquez’s power-study head of Pope Innocent X, courtesy of the National Gallery of Washington (the larger, half-length portrait hangs in Rome's Palazzo Doria Pamphilj; the ever so slightly disputed Houghton/Washington painting is pictured above)?

Oddly, the decision back then would seem to have been the right one. It saved the house, very nearly all of a piece in its resplendently consistent rooms which were William Kent's first major project (Colen Campbell and Thomas Ripley were responsible for the building's noble proportions). The mahogany of the Great Staircase and the carved marble in the Great Hall stun before you catch a whiff of rehang. The staircase’s grisaille mythologies and John Michael Rysbrack’s fantasy classicizing of Walpole, not to mention the French bronze copies of the Borghese Gladiator and the Vatican Laocoön in striking settings, would alone be worth a trip to Houghton. In the rooms proper, the Mortlake tapestries of Stuart royals and their pristine, brightly coloured Flemish counterparts of Venus’s lovers enrich Kent’s rigorous decorative schemes.

But then there’s the picture collection, and most strikingly where its treasures hang, and why. It might seem odd to centralize and glorify Kneller’s very handsome portrait of Grinling Gibbons above the Common Parlour's fireplace (pictured left) when such masterpieces as the Velázquez, Rubens’ Head of a Monk and – surely the most valuable – Rembrandt’s Portrait of an Elderly Lady seem shunted to side and lower places of eminence. But the garland of pear-tree wood around Gibbons’ portrait is surely by the master himself, so that's a neat reunion.

Next page: collecting fashions and Van Dycks among the grapes