Last Monday I moved offices and pondered how the contents of my desk differed to that of my first desk, which was situated just off the Strand in 1974 (in an office building, obviously, not me sat, on the Strand, at a desk outside the Stanley Gibbons shop).

The fundamental change on my desk being there is a PC now and no sign of a Newton’s Cradle (certainly no drinking bird with its nodding head slowly filling up with (in my case) Civil Service tea) – a must for any executive desk (not that I was anything like an executive in 1974).

I did have a typewriter – for younger readers this was like a PC, only with slightly more dexterity needed to type, although it did come with a selection (red and black) of typewriter ribbons; sadly, it didn’t have Tetris.

As well as the example of conserving momentum and energy (who said physics was useless at school?), aside from Newton’s Cradles being on desks, during the 70s, there would always be some form of calendar involving wooden blocks; and if you really were an executive, an angle-poised lamp.

The most senior person in the room would possess the pencil sharpener – scarily not dissimilar to ones you’d have had at primary school, so talking to your boss always left with you the feeling that you’d hope you’d not be tested on your four times table.

But no executive desk was complete without having some form of balancing toy. The trick was to tap the toy and set off the perpetual motion without being too cack-handed and knock it off.  It would be the nearest any of us got to doing gymnastics.

Tomorrow I’m off round the shops in Covent Garden to seek out a 70s executive toy. I wonder if the drinking bird likes Irn Bru?