The British Foreign and Commonwealth Office has located a new cache of colonial-era government documents, VICE News has learned.

The documents, some with "Top Secret" classifications and tantalizing subject titles, originate in the Colonial Office — the long-ago-disbanded government department that oversaw the colonies of the British Empire.

The Foreign and Commonwealth Office (FCO) confirmed to VICE News that the files were located last year, during an audit of government offices that revealed a staggering 170,000 historic files which had never been made public. Some are long overdue for release, and have been held unlawfully, in violation of the UK Public Records Act.

The discovery of the colonial-era documents is likely to arouse unease among historians — some of whom have accused the government in recent years of purposefully suppressing damning material from Britain's Imperial days.

Indeed, this is not the first time that the FCO has uncovered a large trove of long-lost, and sometimes incriminating, historical documents. In 2011 — after repeated denials, and amid a protracted legal battle — the FCO admitted to unlawfully holding 1,500 Kenya files (nearly 300 boxes, occupying 100 linear feet) at Hanslope Park: a sprawling and secretive high-security government compound in Buckinghamshire that the FCO shares with intelligence agencies MI5 and MI6, and where government scientists reportedly develop counter-espionage techniques.

Later that year, the FCO conceded that it actually possessed 8,800 — and, eventually, 20,000 — colonial files, covering 37 former colonies and territories. The government dubbed these files the "Migrated Archives," as if they had drifted, on their own, into the tombs of the Foreign Office.

Some of these documents, which have since been released to the National Archives, paint Britain's colonial administration in a far from flattering light. One file includes a 1953 memo from Kenya's then Solicitor General, who described colonial detention facilities in the country as "distressingly reminiscent of conditions in Nazi Germany or Communist Russia."

The FCO has not made the content of the newly-discovered documents public, but has revealed their general contents.

One box titled "Colonial Intelligence Summaries" is among the historic findings — as are numerous boxes containing material from the Colonial Office's "Intelligence and Security Department" (ISD).

Two boxes hold the ISD's "Top Secret Register." Another two boxes contain ISD documents "related to arms committee, arms traffic etc."

Ten boxes are titled "Colonial Office: Defence (DEF) Top Secret Register" and another box, occupying 0.09 linear meters, houses "Colonial Office: Secret International Relations" documents.

Contacted numerous times by VICE News, the FCO has declined to comment on specific files.

Last year, Cambridge University historian Tony Badger, who was appointed by the FCO to review the colonial files released in 2011, told a group of historians that the Migrated Archive "had been deliberately created. The people who created and administered it knew what they had, knew for a long time, and were determined that others should not know what they had."

In 2013, two years later after the Migrated Archives discovery, the Guardian revealed that the FCO was hoarding another 1.2 million (later, revised down to 600,000) historic documents at Hanslope Park. Some of the files date back to the 1800s. Others detail British relations during the Cold War — and the final throes of Imperial rule.

The purportedly lost files — which the FCO has dubbed the "Special Collections" — reportedly occupy some 15 miles of floor-to-ceiling shelving, including 50 meters of Hong Kong files, 77 meters of "Nazi persecution case files," and the personal desk diary of British diplomat-turned-Soviet spy Donald Duart Maclean. They papers are slowly being reviewed by a team of "senior sensitivity reviewers," who will in some cases redact files prior to their release.

Many of the recently located Colonial Office documents are "registers": essentially, clerical files that often contain records of Colonial Office correspondence, brief details of Colonial Office files, and summaries of any actions taken on those files.

The registers will likely be of interest to historians as documents in their own right. But Dr. Mandy Banton, who worked for 25 years at the National Archives as a Colonial Office records specialist, told VICE News that they might also provide evidence of still more colonial-era documents that the British government has long since destroyed.

That Britain destroyed great hoards of colonial-era files is well documented. For instance, records related to the Batang Kali Massacre — in which British troops killed 24 unarmed villagers in 1948, at the peak of the so-called "Malayan Emergency" — were destroyed in 1966, since they "were not considered worthy of public preservation."

As late as the early 1980s, Britain destroyed boxes of records on colonial Kenya. Historians still do not know the contents of those boxes.

In the early 1990s, the government declared 170 boxes of "Top Secret" British and Overseas Territories files to be lost.

Asked for her impressions of this latest FCO unearthing, Banton, the records specialist, said: "Frankly I am no longer surprised that the FCO is finding more material... Heaven only knows where other material has been stored."

The government has yet to explain why the 170,000 historic files were not turned over to government archives on schedule — or how the FCO "became aware" of their existence last July.

On its website the FCO stresses that its transfer of historic files has been delayed because of staffing difficulties, and because priority has been given to more contemporary files — not because the FCO was trying to keep them secret. "We are not retaining records simply because they are 'embarrassing' or because they shed a particular light on the past."

Follow Katie Engelhart on Twitter: @katieengelhart