Australian travellers have been advised to “exercise a high degree of caution” in Britain amid the “highly likely” chance of a terrorism attack.

The British government raised the terror threat level from “substantial” to “severe” on Thursday (AEST), a day after an antisemitic stabbing in north London.

Australia’s Smartraveller advisory on Friday urged Australians to “be alert to the risks and take official warnings seriously … due to the threat of terrorism”.

The UK’s threat level is at the second-highest out of five, meaning a terrorist attack is highly likely within the next six months.

It follows a stabbing on Wednesday (local time) of two Jewish men in the Golders Green area.

Britain last faced such a threat level in November 2021 after the Liverpool Women’s Hospital bombing and the killing of MP David Amess. It was lowered to “substantial” in early 2022.

Interior Minister Shabana Mahmood said the assessment reflected the latest intelligence and a longer-term rise in extremist threats and was not solely a response to the Golders Green attack.

Officials said the classification came against a spate of recent attacks in London and mounting security concerns linked to foreign states that they said had helped fuel violence, including against the Jewish community.

Starmer, who has faced severe criticism from some in the Jewish community for the government’s response, promised more police ‌in Jewish areas, a ‌crackdown the spread of antisemitism and ⁠new legislation to deal with state-sponsored threats from the likes of Iran.

“People are scared, scared to show who they are in their community, scared ​to go to synagogue and practice their religion, scared to go to university as a Jew, to send their children to school as a Jew, to tell their colleagues that they are Jewish,” Starmer said in a televised statement.

He had earlier been jeered and heckled by a small crowd waving banners reading “Keir Starmer Jew Harmer” when he visited Golders Green where the latest attack took place.

The suspect in the attack, a 45-year-old British citizen who was born in Somalia, had a history of serious violence and mental health issues, police said.

They confirmed he had previously been referred to the counter-radicalisation scheme Prevent in 2020. Local media reported he had been jailed for an incident in 2008 when he stabbed an officer and a police dog.

Amid widespread calls for more ​protection for Britain’s small community of about 290,000 Jews, Starmer said his government would do “everything in our power to stamp this hatred out”.

This included stronger powers to shut down charities promoting extremism and a clampdown on “hate preachers”, ​he said.

The government also ‌said it would fast-track legislation allowing the prosecution of those acting as proxies of a state-sponsored group, so they could be dealt with in the same way as spies for foreign intelligence services.

“We need ​stronger powers to tackle the malign threat posed by states like Iran, because we know for a fact that they want to harm British Jews,” Starmer said.

-with AAP