I am a member of Britain's largest trade union, Unite, and I believe it's now clear that my union's political strategy to radicalise and "reclaim" the Labour Party is incapable of succeeding.

Jim Murphy becoming leader of the Scottish Labour Party is a victory for the most right-wing elements of the party and a colossal blow for the Scottish trade union movement. The battle within Labour between the Blairites and those who want to shift the party back to its working-class roots has been an ongoing narrative for years.

The recent three-way leadership battle, which quickly established itself as a two-horse race between Jim Murphy and the more progressive and left-wing candidate Neil Findlay, has clearly exposed the tension between both sides.

Jim Murphy, backed by an overwhelming majority of MPs and MSPs and leading members of the Labour Party, as well as Scottish Labour students, indicates where the future of the party lies.

The party has bred the Blairities. The pursuit of big business and the championing of neo-liberalism brought in by Tony Blair has continued under current leader Ed Miliband, despite the fact that it was trade union votes that won him the leadership. Non-reversal of Tory welfare cuts and a commitment to the austerity agenda under a future Labour government speaks volumes.

Only this week Miliband once again reiterated his commitment to cuts in every year of the next parliament if he becomes Prime Minister. In that context, Jim Murphy was bound to win.

But what does this mean for the future link between the trade unions and Labour? The Labour Party was created more than 100 years ago in order to be the political voice of the trade union movement and to speak up for the needs of working people. This entrenched historical link has continued in the form of a political levy paid by some of Britain's biggest trade unions. However, given the revival of politics on the back of the independence movement and the upsurge in membership of other political parties, the question arises: should the trade union movement continue to pay millions of pounds to a party that no longer represents its interests?

This is no longer the query of a few radical activists: trade unionists from the top to the bottom of the movement are asking the same question.

In Scotland the question of trade unions' political affiliation to the Labour Party is intrinsically linked to questions about democracy. The dominance of the SNP in Scottish politics and their recent membership surge to more than 90,000 should ring alarm bells for the trade unions. The entire political landscape is changing, with traditional Labour heartlands being lost to political parties whose narratives are positioned much more firmly to the left.

Labour under Murphy can never deliver a left agenda. He will drive Labour further to the right, and continue to alienate the people Labour claim to represent. The unions need a thoroughgoing process of discussion and debate about what type of political representation we need and deserve. The Labour Party was founded because there was a need for ordinary people to have a political voice within Parliament. At a time when people across the country are having to rely on foodbanks to survive, the need for a party that truly represents the founding socialist principles of Keir Hardie's Labour has never been greater.

We need a radical plan to make sure no one has to use foodbanks, to make sure no pensioner freezes to death this winter, to tackle pervasive corporate power, to redistribute wealth from rich to poor, and to democratise our communities and workplaces. No party has been willing to say that they will find a way to raise the money to save Scotland's public services; no ifs, no buts.

Debating the trade union link with the Labour Party should not be something that we are afraid of, but we need a space to do this. That is why I am involved in the Scottish Left Project, which offers the hope of building a new left that can win, like Podemos in Spain and Syriza in Greece. It will not be easy, but funding and backing Jim Murphy to be the next First Minister is not something trade unionists can countenance. Labour cannot be reclaimed. The time for trade unionists to be part of developing a mass, anti-neoliberal alternative is now.

Suki Sangha is a member of Unite the Union and is currently the Vice Chair of the Scottish Youth Committee and a member of Unite's BAEM Committee in Scotland. She also represents young workers on the General Council of Scottish Trades Union Congress and is a signatory of the Scottish Left Project. She writes here in a personal capacity.