MI6: Europe's Most Powerful Intelligence Service – A Peer Review Analysis

The Secret Intelligence Service, better known as MI6, has been ranked the most powerful foreign intelligence service in Europe, according to a peer review conducted by French magazine L'Express. The review, which gathered assessments from 60 current and former intelligence professionals across 25 countries, gave MI6 251 points — a commanding lead over France's General Directorate for External Security (DGSE), which finished second with 169 points. The Netherlands, Ukraine, and Germany rounded out the top five, while Slovakia's service was rated the worst.

The ranking is notable not just for its outcome, but for its method. Each member of the 60-person jury selected five top intelligence services, awarding points from one to five according to their ranking. It's a reputation survey, as Estonian security expert Meelis Oidsalu pointed out, and one that can introduce distortions. "Never before have intelligence professionals themselves — albeit subjectively, but still giving numerical scores — evaluated each other's work," Oidsalu said. "There is certainly news value here, but the sample of 60 respondents is small enough that random distortions can slip in."

Still, the peer assessment carries weight. Intelligence professionals know what constitutes valuable information, and their views reflect real-world capability. The ranking also lacks input from intelligence services' clients — governments and armed forces — which Oidsalu noted as a limitation. But for a community that thrives on secrecy, even a subjective peer review offers a rare glimpse into how Europe's spies view each other.

MI6's Human Intelligence and Technological Edge

The review praised MI6 for its expertise in recruiting high-level informants and penetrating the ruling elites in Russia, China, Iran, and Turkey. This is the classic domain of human intelligence — the slow, patient cultivation of sources inside hostile governments. It's a skill that requires years of groundwork, cultural fluency, and the ability to identify and approach individuals who might be persuaded to share secrets.

MI6's reputation for playing the long game was a recurring theme. The service has been described as having "a taste for dirty tricks," a nod to its willingness to operate in morally ambiguous spaces. But the most concrete example of its effectiveness came with Ukraine. Britain was the first to warn Ukraine about the likelihood of the Russian invasion that began in February 2022, and has been a staunch ally of Kyiv since. Ralph Goff, a former chief of operations for Europe and Eurasia at the CIA, told L'Express: "The British are in the lead on the Ukrainian file. We are right behind them." Robert Gorelick, a former CIA station chief, added: "The United Kingdom has by far the strongest secret services in Europe. MI6 is extraordinary."

That early warning wasn't just a diplomatic gesture — it was a product of intelligence collection and analysis. MI6's ability to penetrate Russian decision-making circles and interpret signals ahead of the invasion demonstrated the kind of high-stakes intelligence work that peer reviewers clearly value.

What the Ranking Doesn't Tell You

While the L'Express ranking focuses on traditional intelligence capabilities, the modern MI6 operates in a world where technology is inseparable from espionage. Cybersecurity, signals intelligence, and artificial intelligence are now core components of any major intelligence service. The ranking doesn't directly assess these capabilities, but they underpin much of what MI6 does.

In the digital age, recruiting a high-level informant might involve encrypted communication channels, digital tradecraft, and counter-surveillance tools. Penetrating a foreign elite increasingly means navigating their digital footprints, from personal devices to social media. MI6's edge in human intelligence is amplified by its ability to use technology to protect its operations and gather intelligence from open and closed sources.

The UK's broader intelligence community, which includes GCHQ for signals intelligence, gives MI6 a technological partner that few other European nations can match. GCHQ's expertise in cybersecurity and data analysis complements MI6's human intelligence, creating a combined capability that is greater than the sum of its parts. This synergy is likely a factor in the peer review's outcome, even if it wasn't explicitly measured.

For global security, the implications are significant. A top-ranked MI6 means the UK is likely to play a leading role in Western intelligence sharing, particularly in countering Russian aggression and Chinese espionage. The Ukraine warning is a case in point: MI6's intelligence helped shape the Western response to the invasion, from sanctions to military aid. As the security environment becomes more complex, with cyber threats and disinformation campaigns, the ability to combine human intelligence with technological tools will be decisive.

Estonia's Surprising Eighth Place

The ranking also placed Estonia eighth, a notable result for a small Baltic nation. Estonia has built a reputation as a digital society, with a strong focus on cybersecurity and e-governance. Its intelligence service, while small, benefits from this tech-savvy environment. Security expert Meelis Oidsalu called the ranking unprecedented, but cautioned that it is primarily a reputation survey. "Their view matters, because they essentially know more or less what kind of information is valuable in intelligence terms," he said.

Estonia's position reflects the changing nature of European intelligence, where smaller nations with specialized capabilities can punch above their weight. Lithuania ranked 18th and Latvia 21st, while Hungary, Bulgaria, and Slovakia received zero points and were left out of the table entirely.

Key Takeaways

• MI6 topped the L'Express peer review with 251 points, ahead of France's DGSE (169 points).
• The ranking is a reputation survey based on 60 professionals' assessments, not a definitive measure of capability.
• MI6's strengths include human intelligence, recruiting high-level informants, and penetrating ruling elites in Russia, China, Iran, and Turkey.
• Britain's early warning to Ukraine about the 2022 invasion was a key example of MI6's effectiveness.
• While the ranking doesn't measure technology directly, MI6's partnership with GCHQ provides a technological edge.
• Estonia's eighth-place finish highlights the growing role of specialized, tech-savvy smaller nations.

What This Means for the Future

The L'Express ranking is a snapshot, not a definitive verdict. Intelligence capabilities are constantly evolving, and the next major crisis could reshuffle the order. But the peer review offers a rare moment of transparency in a world that thrives on secrecy. For MI6, the top spot is a validation of its traditional strengths — human intelligence, strategic patience, and a willingness to operate in the gray zones of international politics.

As technology continues to reshape espionage, the challenge for MI6 will be to maintain its human edge while integrating new tools. The rise of AI, quantum computing, and cyber warfare will test every intelligence service. The UK's investment in GCHQ and its partnership with MI6 suggest it is well-positioned, but the race is far from over.

For those watching from the outside, the ranking is a reminder that intelligence is not just about gadgets and code-breaking. It's about people — recruiting them, protecting them, and understanding what they know. MI6's top spot is a testament to that enduring truth, even as the tools of the trade evolve.