The Conservative Party co-chairman Baroness Warsi has said that by attending the Durham Miners' Gala, Ed Miliband was cosying up to his "militant, left-wing paymasters".
In response Mr Miliband said:
– Labour leader Ed Miliband
"When you see people marching past as I did from the balcony of that hotel, a march people have been doing for 140 years, I think that it is not just about politics, it is about the strengths of these communities.
"The idea that the people here are a bunch of militants, as some of my opponents say, is nonsense."
Labour leader Ed Miliband listed some of the Labour heroes who have spoken before him at past Durham Miners' Galas, including Keir Hardie, Clement Attlee, Harold Wilson and Barbara Castle.
Mr Kinnock was the last Labour leader to attend in 1989, even though Tony Blair's Sedgefield constituency was part of the Durham Coalfield.
– Labour leader Ed Miliband
I am proud to follow in their footsteps. I am proud to be here today.
The stakes are so high in this country. If you are someone who is looking for work, whose living standards have been squeezed, or someone worried about the NHS you're not thinking why's Ed Miliband going to the Durham Miners' Gala, you are thinking what can Ed Miliband do for me.
Ed Miliband has denied he took an electoral risk by becoming the first Labour leader since Neil Kinnock to address one of the country's most traditional trade union events.
Around 100,000 people were expected to attend the Durham Miners' Gala, also known as The Big Meeting.
Mr Miliband took to the balcony of the County Hotel as Labour leaders of the past have done for decades, watching some of the 80 or so miners' banners and around 50 brass bands parade past.
Afterwards he addressed the large crowd on the old Racecourse, where he hit out at the bankers, Rupert Murdoch and "the rip-off" of Britain's energy companies.
Mr Miliband, who is attending with his family, is expected to use his speech to launch an attack on the "divisive" policies of the Tories in government. He is expected to say:
A few years ago the Tories tried to say 'We're all in it together'. But now we know they never meant it. Because we have seen what they do when they get back in power.
One rule for those at the top and another rule for everybody else. They cut taxes for millionaires and they raise taxes on pensioners. It's business as usual in the banks and small businesses go under.
They try and divide our country between rich and poor. Between north and south. Same old Tories. Not building for the future but ripping up the foundations. Not healing our country, but harming it. Not uniting our country, but dividing it.
Ed Miliband will today become the first Labour leader since Neil Kinnock to address the traditional Durham Miners' Gala.
His appearance at the event - billed as the largest remaining working class demonstration in the country - has been warmly welcomed by local trade unionists and party activists.
But the Conservatives said he was "cosying up" to Labour's left-wing union paymasters who secured the leadership for him.
Organisers are expecting a crowd in excess of the 100,000 who attended last year, with trade union members from around the country swelling the numbers at the old Racecourse.