A Swedish woman has been arrested on suspicion of terror offences after landing at Gatwick Airport.

The 40-year-old suspect arrived in the UK on a flight from Italy on Thursday afternoon.

The Independent understands she is suspected of being an Islamist extremist.

A spokesperson for Counter Terrorism Policing South East said she was stopped by police officers under schedule 7 of the Terrorism Act 2000.

“She was subsequently arrested under Section 41 of Terrorism Act 2000 on suspicion of commission, preparation or instigation of acts of terrorism,” a statement added.

Timeline of the Isis caliphate Show all 19 1 /19 Timeline of the Isis caliphate Timeline of the Isis caliphate ISIS began as a group by the merging of extremist organisations ISI and al-Nusra in 2013. Following clashes, Syrian rebels captured the ISIS headquarters in Aleppo in January 2014 (pictured) AFP/Getty Timeline of the Isis caliphate Abu Bakr Al-Baghdadi declared the creation of a caliphate in Mosul on 27 June 2014 Timeline of the Isis caliphate Isis conquered the Kurdish towns of Sinjar and Zumar in August 2014, forcing thousands of civilians to flee their homes. Pictured are a group of Yazidi Kurds who have fled Rex Timeline of the Isis caliphate On September 2 2014 Isis released a video depicting the beheading of US journalist Steven Sotloff. On September 13 they released another video showing the execution of British aid worker David Haines Timeline of the Isis caliphate The US launched its first airstrikes against Isis in Syria on 23 September 2014. Here Lt Gen William C Mayville Jnr speaks about the bombing campaign in the wake of the first strikes Getty Timeline of the Isis caliphate Isis militants sit atop a hill planted with their flag in the Syrian town of Kobani on 6 October 2014. They had been advancing on Kobani since mid-September and by now was in control of the city’s entrance and exit points AFP/Getty Timeline of the Isis caliphate Residents of the border village of Alizar keep guard day and night as they wait in fear of mortar fire from Isis who have occupied the nearby city of Kobani Getty Timeline of the Isis caliphate Smoke rises following a US airstrike on Kobani, 28 October 2014 AFP/Getty Timeline of the Isis caliphate YPG fighters raise a flag as they reclaim Kobani on 26 January 2015 VOA Timeline of the Isis caliphate Isis seized the ancient Syrian city of Palmyra on 20 May 2015. This image show the city from above days after its capture by Isis Getty Timeline of the Isis caliphate Kurdish forces are stationed on a hill above the town of Sinjar as smoke rises following US airstrikes on 12 November 2015 AFP/Getty Timeline of the Isis caliphate Kurdish forces enter Sinjar after seizing it from Isis control on 13 November 2015 AFP/Getty Timeline of the Isis caliphate Iraqi government forces make the victory sign as they retake the city of Fallujah from ISIS on 26 June 2016 Getty Timeline of the Isis caliphate Iraqi forces battle with Isis for the city of Mosul on 30 June 2017 AFP/Getty Timeline of the Isis caliphate Members of the Iraqi federal police raise flags in Mosul on 8 July 2017. On the following day, Iraqi prime minister Haider Al Abadi declares victory over Isis in Mosul Getty Timeline of the Isis caliphate Members of Syrian Democratic Forces celebrate in Al-Naim square after taking back the city of Raqqa from Isis. US-backed Syrian forces declare victory over Isis in Raqqa on 20 October 2017 after a four-month long campaign Getty Timeline of the Isis caliphate Female fighters of the Syrian Democratic Forces celebrate in Al-Naim Square after taking back the city of Raqqa from Isis. US-backed Syrian forces declare victory over Isis in Raqqa on 20 October 2017 after a four-month long campaign AFP/Getty Timeline of the Isis caliphate Trucks full of women and children arrive from the last Isis-held areas in Deir ez-Zor, Syria in January 2019 They were among the last civilians to be living in the ISIS caliphate, by this time reduced to just two small villages in Syria’s Deir ez-Zor Richard Hall/The Independent Timeline of the Isis caliphate Zikia Ibrahim, 28, with her two-year-old son and 8-month-old daughter, after fleeing the Isis caliphate, on Saturday 26 January 2019 Richard Hall/The Independent

“She was detained under TACT and currently remains in police custody. Enquiries continue.”

The offence of preparing acts of terrorism is used for attack plots as well as travelling to join Isis or other terrorist groups abroad.

Jihadis attempting to return to their home countries in Europe from Iraq and Syria frequently take circuitous routes, with multiple stops, in an attempt to avoid the attention of international law enforcement agencies.

Europol’s annual Terrorism Situation and Trend Report, released last week, said the number of foreign fighters returning to the EU was “very low” as hundreds of European men, women and children remain imprisoned in Iraq and Syria.

“Sweden pointed out that almost all their returnees travelled back using their own travel documents,” the report added.

“Their returnees have not been connected to a confirmed plot and most have returned to their former cities, neighbourhoods and groups of friends, and have taken up activities they were involved in before travelling.”

Europol said an estimated 45 per cent of the 900 Islamists who travelled from the UK to Syria and Iraq have returned to Britain, where only one in 10 have been prosecuted.

“Their training and experience – such as handling weapons and explosives – makes them exceptionally dangerous,” it warned.

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“EU member states’ ongoing concern is that these individuals can perpetuate and strengthen their networks both nationally and internationally.”

Europol named Turkey as a key hub for travel, as well as the Western Balkans, Bulgaria, Hungary and Romania.