The voice of Jo Cox has been strengthened rather than silenced and politicians and media must learn from this “act of terrorism”, the Labour MP’s husband has said.

Brendan Cox also said he had “nothing but pity” for his wife’s murderer; 53-year-old white supremacist Thomas Mair.

The right-wing extremist was sentenced to an entire life sentenced at the Old Bailey on Wednesday for killing the mother-of-two in the run-up to the EU referendum.

Speaking outside the Old Bailey, widower Mr Cox said that his wife’s death had prompted “Britain to be at its best: compassionate, courageous and kind”.

“We are not here to plead for retribution,” said Mr Cox, who himself is a campaigner and activist.

"We feel nothing but pity for him, for his life was so devoid of love and consumed by hatred.

“His only way of finding meaning was to attack a woman who represented all that was good about the country in an act of supreme cowardice.

“It was a political act, an act of terrorism, but in the history of such acts, it was probably the most incompetent and self-defeating.”

He also said the family hopes “Jo’s death will have meaning” and that “those in politics and the media” will learn from it.

The Batley and Spen MP was murdered on 16 June, a week before the Brexit vote, at a time of intense campaigning from both sides of the referendum.

A statement from Jo Cox, found in Thomas Mair's house, talked of her support for the Remain campaign Twitter/ Brendan Cox (Twitter/ Brendan Cox)

Mr Cox’s last published blog, from before his wife’s death, was entitled: Why the populist right is winning the refugee debate – and why we should still be optimistic.

“Her voice has been strengthened by all this and not silenced,” said Mr Cox, speaking in a seperate video to broadcast media.

"How she lived is more important than how she died, and what she stood for is more important than the hatred that drove this act."

Jo Cox's sister Kim Leadbetter statement after guilty verdict

He also says that “every other night” he asks people who knew his wife to write a story for the children.

"We have a lifetime of stories. Jo packed in probably 80 or 90 years into the 40 she lived,” he said.

Thomas Mair jailed for life for the murder of MP Jo Cox