Hitting an underarm serve in tennis is considered downright unsporting in stuffy English circles, the sort of thing you associate with an Australian rotter like Nick Kyrgios. The Spanish equivalent, apparently, is cold calling phone customers during a siesta. Hence, under a kind of updated gentlemen's agreement unveiled today, the country's mobile operators have promised to maintain a ceasefire in the battle for business between 3 and 4 in the afternoon, when the whole of Spain is presumably snoozing under a fan after a few lunchtime glasses of Rioja.

Euskaltel, Masmovil, Movistar, Orange and Vodafone are calling it a "code of ethics," making it sound as if they have agreed not to rely on child labor or show bullfights on TV (heaven forbid). Unwanted calls might be deemed unethical by the operators, but to most people they are probably just a nuisance.

While the word siesta does not actually appear in the rules of engagement, there is no other traditional activity scheduled for this timeslot that would explain the "ethics." Calls at certain other times of the day are also now considered unethical, including any time before 10 in the morning or after 9 in the evening. Weekends and bank holidays are out of bounds, too.

Marketeers and sales agents may be wondering when they can make contact. Disturbing someone midway through a lunchtime meatball sounds riskier than a phone call during a fabled recuperative hour that hardly any Spaniards would recognize today. Back in 2017, the BBC reckoned that 60% of Spaniards never took a siesta and that only 17% occasionally took a "midday nap." Respecting the code of ethics would seem to leave just a couple of hours on a weekday morning and what other Europeans might call the early evening.

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The operators that signed the agreement evidently believe they are in tune with their customers. Jean-Francois Fallacher, the CEO of Orange Spain, is quoted saying that "telecommunications operators have adapted our actions over the years to adjust to consumer habits and, how can it be otherwise, be increasingly respectful of their rights and privacy in the business practices we carry out when offering our services."

Surveys would probably show that most consumers don't want to be called at all, unless they are being offered a deal so generous that it would not come from a profit-seeking venture. Amazon, Apple, Google, Microsoft and Netflix only resort to the medium of voice when ageing technophobes – forced by the pandemic to get online – have a meltdown. Judging by the success of the US tech giants, most of us prefer Internet browsing and mouse clicking to an aural assault by a human.

It will be interesting to see if the Spanish move sparks a cultural adjustment to consumer habits in other European countries. British operators would have to avoid approaching customers during afternoon tea or happy hour at the pub. Saturday evenings would need respecting in Finland, while locals are self-flagellating with birch twigs in steam-filled cabins. In France, with its predilection for interminable lunches and 35-hour working weeks, there would be even fewer ethical timeslots available than in Spain.

That country's operators may have decided among themselves that phoning customers in the afternoon is as unsporting as the underarm serve. But the rule setters allow both, and Kyrgios has had success with the occasional cheeky shot. In the cutthroat world of telecom, gentlemen's agreements might not last forever.

— Iain Morris, International Editor, Light Reading