The major security operation under way ahead of Taylor Swift’s London run

Wembley will have more visible security personnel this week, extra video surveillance and hardened cybersecurity, according to experts. Scanners, fencing and bollards are being installed around the perimeter of the stadium. The latest leg of the singer’s global Eras Tour kicks off in the city Thursday.

Increased security measures at the 90,000-capacity venue were being readied after authorities in Austria arrested three teenage suspects over plans to drive a bomb-filled car into crowds outside the Ernst Happel Stadium. The plot forced the cancellation of three Swift shows scheduled to take place at the venue.

“A foiled terrorist plot absolutely heightens the threat and the risk of something happening," said Noah Price, a director at G4S, the company responsible for delivering security for the London 2012 Olympic Games. As a result, organizers would be re-evaluating security protocol and procedures, he said.

A challenge for security officials involves the thousands of Swift fans who travel to her shows without tickets, to celebrate outside venues, sing and trade friendship bracelets, known as “Tay-gating."

“Tay-gating adds a whole new dynamic so they’re having to extend their security perimeter beyond the stadium," Price said.

Wembley has told Swifties not to travel to the stadium without a ticket, warning that fans won’t be allowed to stand or gather outside the venue. Tens of thousands of fans packed a hill overlooking Munich’s Olympic Stadium during a Swift show last month.

“No one is allowed to stand outside any entrance or on the Olympic Steps at the front of the stadium," the venue said in a statement Tuesday. “Non ticket holders will be moved on."

The increased security didn’t deter Jessica Johns from making the journey from Nevada for Friday’s show.

“We’ve been planning this for so long, there was nothing stopping us," said Johns, a 37-year-old bartender from Las Vegas who landed in the U.K. earlier this week.

“They’re clearly beefing up security after Vienna so it will be fine," she said.

Traveling with two friends, Johns said the group were treating their trip like a pretend bridal shower.

“We’ve bought each other gifts and even have T-shirts for each day," she said. One of the group ditched social media for the past year to avoid spoilers ahead of the show.

Swift, who played three sold-out shows at Wembley in June, didn’t comment on the Vienna plot but has in the past talked about her fears of an attack at one of her concerts.

“I was completely terrified to go on tour," she said in a 2019 Elle magazine article, referencing two 2017 incidents: the bombing at an Ariana Grande concert that killed 22 people in Manchester, northern England, and the shooting at a Las Vegas music festival where dozens died.

“There was a tremendous amount of planning, expense, and effort put into keeping my fans safe," she said, adding that she started carrying around army-grade bandage dressings to control bleeding from gunshot or stab wounds.

Security discussions usually involve the artist because they want to safeguard their brand and avoid liabilities, said Don Erickson, the chief executive of the U.S.-based Security Industry Association, a trade group representing more than 1,500 security technology companies.

“They’re not in the dark," Erickson said. “They may not have all the threat intelligence but are going to understand what security protocols look like on site."

The Manchester bombing, which Islamic State claimed responsibility for, resulted in a sea change for large scale events in the U.K., with counterterrorism advice now sought as a matter of course.

Many lessons have been learned since the Manchester attacks when suicide bomber Salman Abedi concealed himself in an area outside the perimeter of the arena and its security personnel, said Dr. David BaMaung, a security and counterterrorism expert who advised the public inquiry into the bombing.

“The inquiry found that the issue of risk assessments at the Manchester Arena was lacking," BaMaung said.

The streets around the stadium Wednesday had a heavy security presence. Groups of committed fans were taking photos in front of the “Swiftie Steps," a mural painted nearby. Access closer to the venue was restricted.

Ella Percy, a 21-year-old from Manchester, said the foiled Vienna attack was scary but that she still plans to go to the Tuesday show.

“I feel like if it wasn’t safe, it wouldn’t go ahead," she said.

She has, however, canceled plans to sit outside Wembley the night before to listen to the music coming out of the stadium. “I don’t want to make it more difficult for security," she said.

The U.K. authorities have been on high alert in recent weeks following a series of violent anti-immigration protests that have swept through several major cities and smaller towns in some of the worst unrest in more than a decade.

The protests were ignited in part by false rumors spread on social media that a knife attack, which left three children dead at a Swift-themed dance class in northern England last month, was perpetrated by an undocumented Muslim migrant.

Three years ago, thousands of ticketless soccer fans violently stormed security at Wembley before England’s European Championship final against Italy. Thousands more caused disorder on the main route leading up to the stadium.

A Netflix documentary called “The Final: Attack on Wembley" was released earlier this year chronicling the chaos.

A government review reported a series of serious security failures surrounding the event, which lead to a significant beefing up of security at the venue, with investment in improving turnstiles, securing entrance gates and installing extra CCTV outside the venue.

London’s Metropolitan Police moved to assure fans that the Swift concerts would be safe.

“London plays host to a significant number of very high profile events each year with millions of visitors having a safe and enjoyable experience," a spokesperson said.

“There is nothing to indicate that the matters being investigated by the Austrian authorities will have an impact on upcoming events here in London," the spokesperson added.

Joseph Pisani and Alyssa Lukpat contributed to this article.

Write to Gareth Vipers at gareth.vipers@wsj.com