MI5 chief: Britain faces greater threat now than after 9/11

Britain faces a more complex security threat than it did at the time of the 9/11 attacks, with terrorism now accompanied by growing threats from states such as Russia and China, MI5 chief Sir Ken McCallum has warned.

Writing exclusively for The Independent on the 25th anniversary of the September 11, 2001 attacks, Sir Ken said the threat landscape had changed significantly since then.

He said the threat from mass-casualty terrorism remained, but was now accompanied by strategic national security threats from capable states.

Citing former CIA director James Woolsey, Sir Ken described the situation as “the worst of both worlds” – with the “dragons” of state threats returning while the “snakes” of radical Islamic extremism persisted.

He called for national security to be treated as a shared responsibility involving government, businesses, academia and the public, rather than being left primarily to intelligence and security agencies.

The UK's terrorism threat level is currently at severe, meaning an attack is highly likely.

Sir Ken said the international campaign against al-Qaeda following 9/11 had significantly reduced the organisation's capabilities, but warned against complacency.

“We must resist the temptation to admire the defences we built yesterday and instead build the ones we will need tomorrow,” he wrote.

He also highlighted the growing threat of state-backed aggression, including sabotage, interference in democratic processes and cyber attacks on critical infrastructure.

“In 2026, unlike 2001, many of the assets, systems and services under threat sit in private sector hands,” Sir Ken wrote, meaning that critical decisions during crises could increasingly be taken in corporate boardrooms rather than solely by government.

He called for closer cooperation between government, industry and academia to address vulnerabilities and respond quickly to future crises.

Sir Ken concluded by saying that the victims of 9/11 and those who could become victims of future attacks were owed “preparation, resilience and the courage to adapt” rather than remembrance alone.

By Aghakazim Guliyev