The sister of Jo Cox has said any resolve for “calmer, kinder politics” in the wake of the Labour MP's assassination has been forgotten.

Kim Leadbeater, whose sister was murdered in her Batley and Spen constituency by extreme right-wing terrorist Thomas Mair on 16 June 2016, said the “language of politics has become even more brutal and toxic”.

Speaking on the eve of the third anniversary of the Labour MP's death, Ms Leadbeater said: “Personal insults and vicious verbal abuse are in danger of been normalised.

“Candidates, MPs and others in public life are subject to intimidation and physical attacks so regularly it has almost become commonplace.

“I worry that we have learnt nothing from what happened to Jo, and I would hate any other family to have to go through what we have been through, and continue to go through, every day.”

Jo Cox tributes - in pictures Show all 20 1 /20 Jo Cox tributes - in pictures Jo Cox tributes - in pictures Floral tributes and candles are placed by a picture of slain Labour MP Jo Cox at a vigil in Parliament square in London AFP Jo Cox tributes - in pictures Tributes to Labour Party MP Jo Cox are placed on her houseboat in Wapping in London REUTERS Jo Cox tributes - in pictures The Union flag at half-mast on top of Portcullis House in London after Labour MP Jo Cox was shot and stabbed to death PA Jo Cox tributes - in pictures Labour leader Jeremy Corbyn (2R) and deputy leader Tom Watson (L) light candles as they attend a vigil to slain Labour MP Jo Cox in Parliament square in London AFP/Getty Images Jo Cox tributes - in pictures Labour Party leader Jeremy Corbyn and deputy leader Tom Watson (rear) arrive to leave tributes at Parliament Square PA Jo Cox tributes - in pictures People leave St Peter's Church after a vigil in memory of Jo Cox REUTERS Jo Cox tributes - in pictures Flowers left at Parliament Square opposite the Palace of Westminste, following the death of Labour MP Jo Cox PA Jo Cox tributes - in pictures People react as they look at tributes left for Labour Member of Parliament Jo Cox in Parliament Square, London REUTERS Jo Cox tributes - in pictures A man writes a message at Parliament Square PA Jo Cox tributes - in pictures People stop to look at tributes left at Parliament Square opposite the Palace of Westminster PA Jo Cox tributes - in pictures A woman arrives to lay flowers at a statue to Joseph Priestly in Birstall near to the scene where Labour MP Jo Cox was shot AFP/Getty Images Jo Cox tributes - in pictures Tributes at Parliament Square opposite the Palace of Westminster PA Jo Cox tributes - in pictures A woman places candles in tribute to Labour Party MP Jo Cox REUTERS Jo Cox tributes - in pictures A member of the public signs a memorial for British MP Jo Cox in Parliament Square, London EPA Jo Cox tributes - in pictures People sign messages of condolence for MP Jo Cox during a vigil in Parliament Square in London Getty Images Jo Cox tributes - in pictures Flags at half mast outside Scottish Parliament in Edinburgh, after Labour MP Jo Cox was shot and stabbed to death in the street outside her constituency advice surgery in Birstall PA Jo Cox tributes - in pictures People arrive in Market Square with floral tributes after the death of Jo Co Getty Images Jo Cox tributes - in pictures Floral tributes are placed in Market Square next to the statue of Joseph Priestley following the death of Jo Cox Getty Images Jo Cox tributes - in pictures Floral tributes are brought to the scene after the death of Jo Cox Getty Images Jo Cox tributes - in pictures A police officer carries bunches of flowers at the scene of the shooting of Labour MP Jo Cox in Birstall REUTERS

She added: “Everybody agreed that we needed a calmer, kinder politics where we treat each other with respect and where violence or the threat of violence had no place.

“Today it feels like all that has been forgotten and the language of politics has become even more brutal and toxic.”

In recent months, right-wing politicians have been pelted with milkshakes while MPs including Remain-supporting Anna Soubry have been on the receiving end of insults outside Parliament.

Since the death of mother-of-two Ms Cox, two annual Great Get Together events have been held in her memory.

A third is due to be held next weekend.