Counter-terrorism chiefs have beefed up their resources to monitor a surge in the number of suspected far-right plotters.
Teams of officers formed to tackle the threat of Islamic extremists have found themselves examining neo-Nazi sympathisers.
Suffolk bedroom bomber Neil Lewington is just one of dozens of white supremacists to surface in recent months.
Officers in West Yorkshire recently foiled an international plot to put guns and explosives in the hands of violent bigots in Britain.
At least 32 people were quizzed and 22 addresses searched across the North of England in April and May.
While in London one senior counter-terrorism officer warned a Muslim community group that attacks may be staged to spark tit-for-tat racial conflict.
And Metropolitan Police Commissioner Sir Paul Stephenson has asked officers to examine what effect the recession could have on far-right violence.
The news mirrors similar warnings of the threat from far-right sympathisers issued in America in recent months.
Assistant Commissioner John Yates, head of Scotland Yard's specialist operations wing, admitted there is "concern" about the threat from far-right sympathisers.
The senior officer confirmed the number of staff working in intelligence-gathering on suspected violent fascists has been increased recently.
But Mr Yates played down reports that right-wing extremists are plotting a murderous terrorist "spectacular".
He said: "There has been concern about some of the far-right issues. We are putting in a small, extra bit of resource in terms of intelligence."
Police chiefs have insisted that al Qaida-inspired terror remains their top priority but admit more resources are needed to counter neo-Nazis.
It is more than 10 years since neo-Nazi nail bomber David Copeland attacked three targets in London in 1999. Three people died at the Admiral Duncan gay pub in Soho.
Copeland also targeted the Muslim community in Brick Lane, east London, and a supermarket in Brixton, south London.
Mark Gardner, of the Community Security Trust, which monitors violence against Jews, said there has been a surge in right-wing incidents.
He said: "Ten years after the Nazi nail bombings in London, we are seeing increasing numbers of neo-Nazis being arrested in their attempts to start some kind of so-called race war."
Last year neo-Nazi Martyn Gilleard was convicted of three terrorism offences and jailed for 16 years.
Officers found machetes, swords, bullets, gunpowder, racist literature and four home-made nail bombs stashed under his bed at his home in Goole, East Yorkshire.Reuse content