When I became leader of the Labour party four years ago, I challenged us to defy precedent by being just a one-term opposition.

Today, I believe we can fulfil that ambition and earn the trust of the British people again. But I also know there is much work to be done to make this happen, work I am determined we will complete over the next seven months.

For all the Conservatives’ bravado and self-congratulation at their conference, the landslide defeat in Clacton and the collapse of their vote in Heywood and Middleton have shown how far David Cameron is from securing the majority they crave. Thursday’s byelections confirmed the discontent across a Britain deeply scarred by division and inequality between a privileged few and the struggles of working people from every walk of life. When the Tories insist that our country is on the right track or claim that there is no cost-of-living crisis, they just prove they are on the wrong side of the bulk of British people who know the recovery has not, for all the ministerial boasting, touched their lives.

But all this does not automatically translate to support for the Labour party. Attention has focused on Ukip as first it recruited Tory MPs and donors and now it begins to win Tory seats. Although it draws much of its support and ideology from the Conservative right, I recognise Ukip is also tapping into a seam of discontent and despair that Labour cannot – and will not – ignore. It is a sentiment that has developed over decades during which industries that used to provide decent prospects have disappeared at the same time as immigration has wrought huge changes in some communities.

People doing tough jobs, trying to provide for their families and give their children a decent shot at succeeding no longer believe they live in a country working for them. Some who feel left behind by our economy and left out of our politics have turned to Ukip in anger, while still more have grown weary about the claims made by all political leaders. Our task is to turn the despair and cynicism on which Ukip thrives into a positive force for change. We can only do so if we understand that many people are turning to Ukip because of disappointment with Conservative and Labour governments. From my first day as Labour leader, I have been clear that the next Labour government would neither just pick up where the last left off nor risk ignoring the legitimate concerns of working people.

That is why we have developed a new approach to immigration. We will neither follow the Tories in making promises they cannot keep nor try to ape Ukip by conniving with the pretence that all the problems of working people would be solved by turning our backs on Europe. Instead, we are responding to people’s concerns in hard-headed fashion: recognising how immigration has helped our country as a whole but setting out effective measures to prevent the undercutting of pay or loosening the ties that bind our communities together.

I will not cede the issue of immigration to those offering fear or falsehood. So I will continue to chart a new way forward, combining stronger border controls and laws to stop the exploitation that has undermined wages of local workers, with reforms to ensure those who come here speak English and earn the right to any benefit entitlements. Such measures are part of a compelling and credible plan for Britain’s future that will restore the values people believe in – contribution, responsibility, fairness – to the way our country is run.

We will reward hard work, which is why we are the only party committed to raising the minimum wage to £8, significantly closer to average earnings, as well as truly ending the abuse of zero-hours contracts. And our goal of raising living standards means wholesale change in the way our economy works – from bank reform and energy prices to real support for small businesses and the self-employed – so we can restore the link between family finances and the wealth of our nation.

Labour will transform young people’s prospects by revolutionising vocational education, ensure that as many school-leavers get an apprenticeship as go to university, and double the number of first-time home-buyers. And we will invest in our NHS so it meets the challenges of this century as it did in the last by paying for the thousands of extra nurses, doctors, home-care-workers and midwives needed for them to have the time to care for patients and relieve pressure on hospital services.

I will never take for granted the votes of people from communities that have traditionally supported Labour. But, far from appealing only to a so-called core vote of those who supported us at the last election, our plan is built on the understanding that discontent runs wide and deep across our country. Those caught in the cost-of-living crisis include young families in Carlisle and pensioners in Cannock Chase. Fears for the future of our NHS are felt in Milton Keynes as they are in Merseyside. And the belief that our children should have the chance to get on is fundamental to our country – it is the Promise of Britain.

So our plan reaches out to those people Old Labour never reached and those New Labour left behind to help us build a One Nation Labour majority. Over the days to come, we will continue to develop all these aspects of our plan – wages, jobs, opportunities, homes, immigration and our public services. The mood of our country demands more change, not less, but also change that is credible. And, because our plan is built on solid economic foundations with a tough approach to the deficit – balancing the books in the next parliament with the debt falling and a surplus on the current budget – we will show where the money comes from for all our policies.

Labour’s NHS Time to Care fund will raise £2.5bn a year from the top, including hedge funds avoiding their fair share of tax, and houses worth more than £2m. The Tories cannot match the ambition or the discipline of our plan. This prime minister opposes our tax on the most expensive properties in Britain but announces proposals for a squeeze on the working poor combined with billions of pounds in unfunded tax cuts with still more benefits for people earning £100,000 a year. Over the next seven months, Labour will fight for change on all fronts: against Conservatives who only stand up for a privileged few; against Ukip, which is more Tory than the Tories; and against the Liberal Democrats, who have become a byword for distrust in politics.

Our best weapon will be the real hope offered by our plan for our country’s future. And I relish the battle ahead to win a Labour majority that will bring the change Britain needs.