Professor Matthew Feldman, who has given evidence in 40 convictions of radical right extremists in the UK, said the conditions in the next six months are "absolutely stark" and there is a "real recipe for crisis".

He said the far-right variant of what he calls "self-directed terror" is on the rise globally, fuelled by the glorification of mass murderers such as Norwegian Anders Breivik.

"If we think about what drives far-right extremism, it tends to be political crises, and social crises, or at least the perception of social crises," he said.

"Right now the conditions in Britain are absolutely stark, indeed blinking red, that the political and social crises are only going to deepen over the next six months."

He added it was a "real recipe for crisis" when an average wage earner is struggling to make ends meet on £25,000 a year in many parts of the country.

"Most desperate people suffer silently with anxiety or going to foodbanks, but we also know that desperate people can do desperate, horrible, things," said Prof Feldman.

"My genuine concern is that we're heading into a period of protracted crisis and there doesn't seem to be a great deal of joined-up thinking about what that crisis means and how it can be ameliorated, and indeed on how that crisis could very quickly spin out of control."

Prof Feldman identified a "bloody triangle" of factors that can lead to far-right terror.

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He said these included the concept of self-directed attacks, the spreading of ideology online, and far-right terrorists being hailed as "saints or martyrs".

He identified at least five lone wolf attacks over the last seven years, while highlighting the continuing success of counter-terrorism police in foiling more plots.