The Robert Pocock boozer, in Gravesend, used the ruling, which can be applied in all Wetherspoons pubs, after drunken parents caused problems for the staff.
Posters informing punters of the prohibitory policy were put up at the Kent branch of the popular pub chain last week - following reports of "unruly behaviour".
The notice at the Robert Pocock boozer, in Gravesend, has since been taken down but the ban, which can be enforced at the discretion of individual managers nationwide, remains in place.
The controversial poster read: "As part of our licensing it is our responsibility to ensure that we are protecting children from harm. Therefore adults in charge of children will be allowed to have one alcoholic drink and a further alcoholic drink with a sit-down meal."
It went on to add after the limit had been reached staff would have the "legal right to refuse service of alcohol" to customers and that though the policy had not been "followed rigorously" in the past, it would be taking the policy forward this year.
According to a 1902 licensing act, it is illegal to be drunk while in charge of a child under the age of seven, anyone found in contravention of the rules can face a fine - or even a month behind bars.
Publication of the notice sparked fierce debate on social media, with parents and bloggers declaring that it was "yet another example of parent shaming" and stating that it was a "nanny state" move.
Others then countered this by stating that Wetherspoons "was not a nursery".
Customer Jonjo O'Connell said he agreed with the rule "in principle" although felt enforced in isolation it might be open for abuse.
He said: "Considering the type of parent it is aimed at, a pub is not a creche and I think some parents seem to forget that.
"Although I anticipate the rule will be circumvented by some just going around the corner to The Goose and staying there or returning later to the Pocock when a different shift arrives."
Wetherspoon spokesman Eddie Gershon said: "The notice was briefly up in the pub, but this is no longer the case.
"The manager took the decision to put the poster in the pub to emphasise to customers that she would not allow parents to drink whilst their children were running around uncontrolled in the pub. The notice had had a positive effect, with mostly good feedback."