Humour is the best recipe for friendship, as the Queen shows

Laughter lines: the Queen is said to have a strong sense of humour, which she shares, above, with the Duke of Edinburgh

How gladdening to know that the Queen is close friends with Sir David Attenborough. It’s enough to make us want to tear up our dream dinner party guest lists and opt to be a fly on the wall at their afternoon tea instead.

Humour is the glue in enduring friendships and, as attested by new pictures of the pair, both aged 91, they never fail to amuse one another.

I’m not sure I’ve seen Her Majesty quite so giddy since her bay filly Estimate won the Gold Cup at Ascot in 2013, and I can’t help beaming, too.

Although she is not a monarch given to public displays of emotion, our Queen is reported to have a sharp sense of fun, albeit usually expressed behind closed doors. Or with trusted friends.

She and Sir David were filmed walking in the Palace gardens as part of a forthcoming documentary highlighting a Commonwealthwide conservation project to create a network of national forest parks.

They had lots to say because they share a passion for nature – and a passion for life. Yes, they have a sense of the legacy they will leave behind, but in their ninth decade, they also know the truth of Shakespeare’s acceptance: “With mirth and laughter let old wrinkles come.”