The number of prisoners classed as right-wing extremists who are behind bars for terrorism offences has almost doubled in two years, figures show.
In the year to the end of December, there were 41 people in custody categorised as holding extreme right-wing ideology, according to the Home Office data.
This shot up from just a handful of cases five years ago (four in 2014) to 21 for the same period in 2017 and 28 in 2018.
The figures follow a decision by MPs to back a ban on membership of more right-wing terrorism groups.
Overall, there were 231 people in custody for terrorism-related offences in Britain in the year to the end of December.
The “vast majority”, 77% (177), were branded as holding Islamist-extremist views, the data report said. This number has remained largely the same as last year. A total of 18% were categorised as holding far right-wing ideologies.
The report said: “The proportion of prisoners holding far-right ideologies has increased steadily over the past three years.”
The figures, which count convicted prisoners and those being held on remand, also recorded 13 inmates who were not classified as holding a specific ideology.
Last month a proscription order was issued which makes joining the organisation Sonnenkrieg Division illegal in the UK and lists Teyre Azadiye Kurdistan (TAK) and Hezen Parastina Gel (HPG) as aliases for Partiya Karkeren Kurdistani (PKK), which translates as the Kurdistan Workers’ Party.
The law will also recognise System Resistance Network as an alias of the already banned neo-Nazi group National Action.
Anyone found to be a member of, or offering support to, the groups could now face up to 10 years in jail.
There were 42 convicted terrorists released from jail as well as 12 suspects who had been held in custody but not sentenced in the year to the end of September, according to the report. Figures to December are not yet available.
The number of arrests for terrorism-related activity has dropped to the lowest number in six years (280 to December 30) but rose in the last quarter and remains higher than the annual average of 260, according to the report.
Of these, 110 (39%) were released on bail or released under investigation – meaning they were not subjected to any restrictions while inquiries into the offences continued.
There were 87 (31%) charged and 65 of these were for terrorism-related offences.
A further 19 (7%) received a caution, were recalled to prison or handed over to immigration authorities and 63 suspects (23%) were released without charge.
Commonly, sentences are consistently less than four years and were handed down for more than half of the convictions (24 out of 46).
Three offenders in the last year were handed a life sentence, down from six in the previous year, but the number of long-term sentences of more than 10 years rose slightly.