As tens of thousands of “Swifties” make their way towards the concert venue on Thursday, at 5pm a siren will wail out across the city to mark the exact time that Polish resistance fighters rose up against Nazi oppression 80 years ago.

Every year, traffic and people come to a standstill at that time to hold a minute’s silence in memory of those who died during the Warsaw Uprising.

Commemorated every year by the city’s residents, the Uprising which started on 1 August, 1944 and lasted 63 days ended with over 80% of the city being razed to the ground.

Around 18,000 insurgents were killed during the brutal fighting, another 25,000 were injured and over 180,000 civilians died in German mass executions and bombings.

But city authorities now fear that nationalists, who traditionally gather at the capital’s Dmowskiego roundabout before letting off red flares and marching through the city, could turn on the fans.

Many Taylor Swift fans are coming from abroad and may not be aware of the anniversary’s cultural significance and there are concerns that nationalists may consider them disrespectful.

Announcing a special “collision-free” transport policy, City Hall spokeswoman Monika Beuth said: “The president has called a crisis team to discuss the matter.

“We are thinking about how to ensure safe transport for thousands of guests.

“And we advise travel by metro line II to the Stadion station [to avoid routes used by rightwing groups]. The metro will run before and after the concert with greater frequency.”

Officials have also asked the concert organizers to send information to each ticket holder that sirens will sound in connection to the Uprising anniversary and that a demonstration will be held at Dmowskiego roundabout.