French nudists have issued a threat to “bare all” in a stand-off with burkini-wearing bathers at public swimming pools in the French city of Grenoble, as temperatures of over 40 degrees Celsius hold a relentless grip on western Europe, reports The Telegraph.

The city residents have launched a “citizens’ secular, ecologist” Facebook group called “Everyone Naked”, as they summoned members to arrive at the pool naked and challenge the “burkini brigade”, deploring Green mayor Eric Piolle’s “worrying inaction”.

At least 231 protesters have expressed an intention to arrive naked, with 1,300 showing an interest.

Soaring temperatures in Grenoble had stoked already-flaring passions among local residents, as authorities had shut down the city’s two municipal swimming pools after Muslim women were seen swimming there wearing burkinis.

The burkini-clad women went to the pools twice at the initiative of Alliance Citoyenne, a civil rights NGO, to challenge a city ban on the full-body swimwear, which they claim is discriminatory.

For reasons of security and hygiene, the southeastern French city obliges women to wear one-piece close-fitting bathing costumes in swimming pools while men must wear Speedo-style swimsuits rather than shorts.

However, in a deliberate act of defiance, the group of Muslim women challenged the ban.

Initially, some 15 women managed to enter the pool on 17 May and even filmed themselves bathing, claiming they sought to “to defend freedom of religion”.

​Last Sunday, the ladies were fined €35 (£30) each for doing so.

Nonetheless, the women went on social media to call for a third such “operation burkini” this Sunday.

The burkini advocates say they decided to act after 630 people signed a petition asking for the rules to be changed so Muslim women could bathe in public baths.

​Adrien Roux, national head of the Citizen’s Alliance, deplored the fact that due to their religious beliefs, hundreds of Muslim women couldn’t go swimming.

The embattled city mayor has now called for the state to intervene to “remove all ambiguity on the status of body-covering swimming costumes”.

2016 witnessed several French municipalities banning the wearing of burkinis, claiming it was a security threat, only to have the bans later overturned by a court.

© AFP 2019 / FETHI BELAID

Tunisian women, one (R) wearing a “burkini”, a full-body swimsuit designed for Muslim women, swim on August 16, 2016 at Ghar El Melh beach near Bizerte, north-east of the capital Tunis.

A modesty swimsuit for women, the burkini covers the whole body except the face, the hands and the feet, in a design intended to respect Islamic traditions of modest dress, but its acceptability is debated.