Of course we are away from home when I download this week’s Listener. When Chambers and Mrs Bradford are not comfortingly on the table, we invariably download a Sabre, Quinapalus, Mash or a Shark. We are enjoying the end of season festivities of friends who operate activities in Morzine – a jolly ‘knees up’ with local musicians and traditional wine and song. The last thing we need is a tough solve, even if it is bound to be rewarding, compiled, as it is, by a previous Ascot Gold Cup winner.

Does Shark still qualify for his place in the Listener Setters’ Oenophile Outfit? I scan the clues and have to say “Only just!” ‘Looked after old drunk (8)’ gives us a rather surprising double definition clue. I didn’t know that ‘overseen’ could once mean drunk. However, things become more interesting when we get to ‘Colour of seabed gunk dissipated’ (11)’ We discard the K from the anagram of OF SEABED GUNK and produce SANG-DE-BOEUF. Yes, that gives the colour red, but bulls’ blood has an intriguing past in the wine industry where, until it was banned during the ‘mad cow disease’ period, powdered bulls’ blood was used to clarify red wines here in France.

It gets better. Sangre de Toro is near to the bottom row of any Spanish supermarket shelf and we have quaffed a considerable quantity of it in our time so a hearty “Santé, salud, Shark”.

Yes, those were subtle clues and we could say that of most of the others too and we struggled our way to a grid fill, breathing a sigh of relief when we managed, for example to find a clash when two more generous clues, this time giving us an extra N (‘Wild rat (6)’ = DESERT and ‘River rising in Massif Central’s small lake (4)’ = TARN).

SOFI clashed with LIMBIC, BUMS clashed with VISEED, SALSE clashed with DAYDREAMERS, NEALE clashed with SEE A WOLF, and TAK clashed with AIRGLOW, and by opting for real words each time, we teased out an intriguing BEN FRANKLIN and, with the title Bright Spark had an inkling of the theme. The single letters we have been dropping from ‘clues that do not result in a clash’ confirm our suspicion. We have SHEET, FORKED, CHAIN, BALL and BLITZ so that we know that it is LIGHTNING that we are going to find and highlight in nine letters undoubtedly coming from the heavens.

Wikipedia obliges, as usual, and confirms that we need a wet hemp string, a kite, a key and a Leyden Jar

‘According to the 1767 Priestley account, Franklin realized the dangers of using conductive rods and instead used the conductivity of a wet hemp string attached to a kite. This allowed him to stay on the ground while his son assisted him to fly the kite from the shelter of a nearby shed. This enabled Franklin and his son to keep the silk string of the kite dry to insulate them while the hemp string to the kite was allowed to get wet in the rain to provide conductivity. A house key … was attached to the hemp string and connected to a Leyden Jara; a silk string was attached to this. … The kite was not struck by visible lightning; had it been, Franklin would almost certainly have been killed. However, Franklin did notice that loose threads of the kite string were repelling each other and deduced that the Leyden jar was being charged. He moved his hand near the key and observed an electric spark, proving the electric nature of lightning.

It is in hunting for these ‘four components’ that we realize what a masterful compilation this is. KITE and STRING give us ten letters and we extend them with twelve more, LEYDEN JAR and KEY, but wonder how we can find a ‘related 6-letter word’ that can be ‘traced twice, starting from the same cell’ and then in a metaphoric flash of lightning, we see that STRIKE goes up through the kite and down the STRIng and into the KEy.

We do our sketch of the thematic outcome but Shark hasn’t finished yet. We still neeed to drop letters to the ground, producing ELECTRICITY and retaining real words. Brilliant indeed!