Last week, Lord Mandelson called on Jeremy Corbyn to seek ‘unity right across Labour’s broad spectrum’ and ‘embrace more centrist’ voters in our push for No.10.  His words were no doubt met with rolled eyes by some in the Party. That tends to be the case whenever some, including Mandelson, make an observation based on their own experience of the last time we were in government.

In truth, his advice should be heeded. In this instance he is absolutely spot on.

Jeremy and his team have captured the imagination of many people with a fresh perspective on the issues we face today – Corbynism is now an established, and growing, force. The Labour Party is asking British society what it prioritises and saying that – to deliver an agenda based on fairness and equality – we need to really change a few things, not just fiddle around the edges. That is welcome and that is resonating.

We should not shy away from our message that society needs a shake-up and we have to be bold about how we go about it. In the process, we need to consider a whole host of options – that’s why corporation tax changes and the nationalisation of certain industries to serve in the public interest are, indeed, on the table.

But in being bold, we should not be rash. By rightly reinvigorating parts of the Labour movement we should not neglect others, nor should we lose sight of the realities of the electorate. In doing so, we may win over ourselves, or a core of individuals (which Mandelson labels ‘sectarian’ supporters), but we will not win an election. The truth remains that to win, and win well, the Labour Party has to earn the votes of those who previously haven’t voted Labour. That don’t spend their time living left-wing politics – or even politics at all. When Lord Mandelson calls for Labour to reach out to ‘centrist’ supporters he’s got those people in mind. Some of whom will have voted Conservative previously – and may well do so again.

There is of course a recognised counter case here – that, by engaging especially with young people and those who previously didn’t vote at all, Corbynism is doing more to bring in Labour voters than ever before. There’s certainly a lot of truth in this, as the last General Election showed.

But this strategy should not be at the detriment of retaining – and renewing – the support of those voters who have always considered themselves Labour, or have sometimes flirted with the idea of voting Labour, but are a little hesitant now to get behind what they consider as a very left turn. Perhaps they are a little older and have seen such a left turn fail to deliver before, or perhaps they aren’t ready to clear their lungs for the next chorus of ‘Oh Jeremy Corbyn’ because, in truth, they feel a bit weird doing that.

Either way – they are, or could be, Labour, and must be part of the regeneration of this movement too. They need to be heard and their views understood.

Above all, we need to persuade – and debate with – prospective supporters, voters and indeed opponents, not to lecture. It is so, so, important that the Party does not become so evangelical that it immediately dismisses the views of others, or confuses healthy debate with dissent.

To do so would actually work to undermine the narrative of inclusiveness that is integral to the appeal of Corbyn’s outward-facing message to the country. As a Party, we need to practice what we preach – within the Labour movement, and outside of it.

Doing so will only support our growth and broaden our appeal. Two things that can, and will, help us to win next time round.

James English was the Labour Party Candidate for Beaconsfield at the 2017 General Election. He (sometimes) tweets here: @_jamesenglish