The rule was introduced in 2016 after a spate of majors were won by golfers using extended putter shafts.

Keegan Bradley anchored in his midriff to win the 2011 US PGA, as did Ernie Els for his Open triumph the following year. There were broom-handle major wins for Webb Simpson in the 2012 US Open and Adam Scott a year later at the Masters. The Aussie continues to use the long putter, but with daylight between his stroke and his body.

Protecting the “fundamental characteristics of the putting stroke” was the reason for banning anchoring nine years ago.

It is OK for an extended shaft to be clamped against a forearm (as US Open champion Bryson DeChambeau does) because that moves to make the hit.

But there are those in the game who feel even this technique makes putting “too easy”.

And there are plenty more exponents who continue to shun convention and go with longer implements. Along with Schmid, the likes of Akshay Bhatia, Si Woo Kim and Lucas Glover use these potentially contentious clubs to great effect.

Bernhard Langer and Scott McCarron have long endured their techniques being questioned on the Seniors tour, and Spaniard Eugenio Chacarra’s Indian Open win on the DP World Tour last March drew focus.

Langer and McCarron have vehemently denied breaching the rules.

Back in 2017, Langer said: “I personally don’t understand it because I’m a man of integrity, and the last thing I want to do is break rules and be known as cheating.

“I know when I’m anchoring and when I’m not anchoring because I control my hand. It goes sideways, you can see it.

“So when my knuckle is away from the body, I’m not anchoring or touching any part of my body and I know I’m within the rules.”

The problem is that in many cases it is not evident to the naked eye and is impossible to enforce either way.

It means an issue as fundamental as the putting stroke is shrouded in more grey areas than a flotilla of battleships, which is highly unsatisfactory and not fair on the likes of Schmid when they dominate so brilliantly on the greens.

DP World Tour winner Eddie Pepperell believes the solution is “quite simple”.

“Insist on the putter being the shortest club in the bag,” he told the Chipping Forecast podcast.

Some referees agree.

“Easy solution is just limit the maximum length of the putter and be done with it,” said one official.

Another said: “The powers that be should be looking at it. If there is a rule, we should be able to enforce it.”