Britain First leader Paul Golding has condemned the attack on Jo Cox MP as 'an attack on the very fabric of this country'.
After it was reported the shooter chanted "Britain First" during the attack, Mr Golding said it was too early to speculate - but added: "Could this person have shouted 'it's time to put Britain first?'"
The leader of the far right movement said: "She has been out campaigning to keep Britain in the EU and there are people in the area that are against it.
"An MP is in hospital fighting for her life. It's disgraceful.
"I don't think it was one of our supporters. We stand in elections and organise protests - we don't encourage this kind of nonsense.
"She has a young family - an attack on a mum like that is disgraceful.
"Whether you agree with Labour, to have had that happen to her on the streets is shocking and an indictment of the state of this country.
"God bless her and I hope she does get better."
Jo Cox murder - how events unfolded
How events unfolded during the day
The MP in profile
Everything we know about what happened
Britain First leader says killer 'probably wasn't a member' of far right group
Jo Cox has tragically died of her injuries
Jo Cox obituary
Jo Cox's husband Brendan's statement
Police statement in full
Hero police tacked suspect despite being unarmed and not wearing stab vests
Tears and sadness at the vigil in Jo's memory
Book of condolence opened in Batley
A local campaigner
More than £1,000,000 raised for Jo
Online condolence book
Terrorism link probed
Thomas Mair charged with murder
Mair's first court appearance
"He never spoke to anyone"
Tributes from Jo's devastated family
A hero tried to save her
"A good Samaritan"
Main parties won't contest Batley and Spen seat
MPs wore white roses in Jo's honour
Hero Bernard Kenny who tried to save Jo
Tributes to JoLight sculpture created for Jo Cox memorial service in Huddersfield tonight
People pay tribute to Jo on her birthday
Mair's first appearance in crown court
MPs pay tribute in parliament
More than £1,000,000 in four days in Jo's memory
Calls for Bernard to receive the highest honour
Jo worked hard to support refugees