Historian Niall Ferguson says Britain could have lived with German victory and should have stayed out of war

Britain could have lived with a German victory in the first world war, and should have stayed out of the conflict in 1914, according to the historian Niall Ferguson, who described the intervention as "the biggest error in modern history".

In an interview with BBC History Magazine, Ferguson said there had been no immediate threat to Britain, which could have faced a Germany-dominated Europe at a later date on its own terms, instead of rushing in unprepared, which led to catastrophic costs.

"Britain could indeed have lived with a German victory. What's more, it would have been in Britain's interests to stay out in 1914," he said before a documentary based on his book The Pity of War, which will be screened by BBC2 as part of the broadcaster's centenary season.

The Laurence A Tisch professor of history at Harvard University rejected the idea that Britain was forced to act in 1914 to secure its borders and the Channel ports. "This argument, which is very seductive, has one massive flaw in it, which is that Britain tolerated exactly that situation happening when Napoleon overran the European continent, and did not immediately send land forces to Europe. It wasn't until the peninsular war that Britain actually deployed ground forces against Napoleon. So strategically, if Britain had not gone to war in 1914, it would still have had the option to intervene later, just as it had the option to intervene after the revolutionary wars had been under way for some time."

It was remarkable, he said, that Britain intervened on land so early in 1914, when quite unprepared.

"Creating an army more or less from scratch and then sending it into combat against the Germans was a recipe for disastrous losses. And if one asks whether this was the best way for Britain to deal with the challenge posed by imperial Germany, my answer is no.

"Even if Germany had defeated France and Russia, it would have had a pretty massive challenge on its hands trying to run the new German-dominated Europe and would have remained significantly weaker than the British empire in naval and financial terms. Given the resources that Britain had available in 1914, a better strategy would have been to wait and deal with the German challenge later when Britain could respond on its own terms, taking advantage of its much greater naval and financial capability."

The comments are certain to fan the flames of the debate sparked by the education secretary, Michael Gove, about whether Britain's role in the war should be seen as heroic courage or monumental error.

Gove, in an article in the Daily Mail, attacked "leftwing academics all too happy to feed those myths by attacking Britain's role in the conflict", and decried the Blackadder portrayal of the war as "a series of catastrophic mistakes perpetrated by an out-of-touch elite".

Ferguson is unequivocal: "We should not think of this as some great victory or dreadful crime, but more as the biggest error in modern history."

He continued: "The cost, let me emphasise, of the first world war to Britain was catastrophic, and it left the British empire at the end of it all in a much weakened state … It had accumulated a vast debt, the cost of which really limited Britain's military capability throughout the interwar period. Then there was the manpower loss – not just all those aristocratic officers, but the many, many, many skilled workers who died or were permanently incapacitated in the war.

"We need of course to feel sympathy for the men like my grandfather who fought in the first world war, because their sufferings were scarcely imaginable. The death toll, which was greater than the second world war, was the most painful thing that Britain has ever experienced in war."

But, he added, we should also feel dismay that the leaders, not just of Britain but of the European states, could have taken decisions that led to such an appalling slaughter.

"Arguments about honour of course resonate today as they resonated in 1914, but you can pay too high a price for upholding the notion of honour, and I think in the end Britain did."

He concedes that if Britain had stood back in 1914, it would have reneged on commitments to uphold Belgian neutrality. "But guess what? Realism in foreign policy has a long and distinguished tradition, not least in Britain – otherwise the French would never complain about 'perfidious Albion'. For Britain it would ultimately have been far better to have thought in terms of the national interest rather than in terms of a dated treaty."

Ferguson, no stranger to controversy, is unlikely to worry about coming under fire for his views. Last year he managed to stir up a massive row over a long-dead economist when he suggested that John Maynard Keynes had no stake in the future because he was gay and childless – although he did later apologise, calling his remarks "stupid and tactless".