Ed Miliband called for a "better Britain" as he outlined his bid to become the UK prime minister to the Labour Party faithful in Birmingham on Saturday (14 March).
The Labour leader also attacked David Cameron's record and blasted the prime minister for refusing to take part in a head-to-head TV debate with him.
"It is not leadership to be strong in the face of the weak, but always weak in the face of the strong," he said. "And it is certainly not leadership to claim to be a strong leader but to refuse to defend your record in front of the British people in a TV election debate."
During his keynote speech Miliband unveiled Labour's main election pledges, 54 days before the 7 May vote.
The five pledges included a promise to "balance the books" and cut the UK's deficit every year, higher living standards for working families, more healthcare staff for the NHS, controls on immigration, and a country "where the next generation can do better than the last".
The Labour leader reiterated his party's pledge to keep the UK in the European Union (EU), arguing that pulling out would cut Britain off from the rest of the world.
"We will never put up with a country where we cut ourselves off from the rest of the world," he said.
"Because the Britain I believe in is outward looking, engaged in Europe, and doing our duty to the world.
"We will never put up with a country where power is hoarded in Westminster, with people deprived of the chance to shape their own lives.
"Because the Britain I believe in is one where we seek power, in order to give it away."
Miliband cantered his speech on the "Britain I believe in" line and called on the electorate to judge the UK's success "by the success of working people".
"It is that we understand that it is only by working people succeeding that can we succeed as a country," he argued.
The Number 10 hopeful made the speech at Labour's spring rally at Birmingham's International Convention Centre.
Simon Franks, a co-founder of Lovefilm, also addressed the audience. Franks stressed that as a businessman he would be campaigning and voting for Labour at the general election.
The comments come after business leaders, like Boot's Stefano Pessina, attacked Miliband's business credentials. The speech from Franks was a clear attempt at countering criticism that the Labour Party is anti-business.
The West Midlands event also saw some star power in the shape of Broadchurch's Shaun Dooley.
The Barnsley-born actor compared his experience growing up during the miners' strikes, when his family fell on hardship, to the modern day surge in food banks across the UK.
Dooley also weighed in on the row over Miliband's two kitchens, joking that Labour should throw everything at the Tories in the run-up to May, "including both kitchen sinks".
The comments come as the latest poll from YouGov put the Tories one point ahead of Labour 0 33% vs 32% – as the general election approaches.