On election night in May 2010, I was studying in Italy. I’d crashed out on a friend’s sofa at about 4am, having come back from a bar to shout at the television. When I woke mid-morning, both parliament and I were hanging. Many of you will remember that morning. But this is a column for those who were too young to vote in that election.

A year later, I graduated into a recession with more than £30,000 in student debt – peanuts, of course, compared with the debts faced by today’s students – but it was still intimidating. Many of my peers had voted Liberal Democrat in 2010 because the party had promised to abolish tuition fees. We knew how it felt to be burdened with huge student debt.

They overlap with the vanishing 'moderate' wing of the Tories – whose MPs are now defecting to the Lib Dems

Almost a decade on, the UK is very different. For almost my entire 20s, politics has been dominated by the Conservatives. First they were propped up by the Lib Dems, who went into coalition and reneged on their election campaign promises, voting with the Tories to raise tuition fees and impose austerity. And then, after just two years with a majority, the Tories were rocked at the polls but limped on with the support of the anti-abortion religious fundamentalists of the DUP.

Now, there are homeless people everywhere, food bank use has skyrocketed, the housing crisis has worsened, the right is now the far right, zero-hours contracts are common, and just over half the country has voted to take away its citizens’ ability to live and work in 27 European countries.

Racism has become normalised. An MP has been murdered, many others threatened and harassed. Disabled people, migrants and black British citizens face a hostile environment. In 2010, I was young and idealistic. This past version of me, hungover on a sofa in Italy, would find the country today unrecognisable.

I don’t want the same thing to happen to today’s young people – you don’t get your 20s back. Whatever government is in power creates the conditions under which your life unfolds.

Don’t be deluded by the claim that everything that happens to you is down to you and your work ethic, and that people who do not succeed simply didn’t try hard enough. The housing policy of the day plays a huge part in whether you own a home (many of my friends still don’t, and a lot of those who do received money from their parents). The availability of free childcare – or the presence of a local Sure Start centre – affects decisions on when or whether you have kids (many of my group still don’t, and many of those who do are raising them in insecure rented accommodation).

I feel in my bones that, had I spent my 20s governed by Labour, not only would the country look profoundly different but perhaps my life would be too.

Now the Lib Dems are again trying to lure voters from the centre left with big promises. This time, instead of talking about tuition fees, they say they will revoke article 50. Everyone knows this will never happen: even the Lib Dems themselves. But they know this message will take votes away from Labour, and Lib Dem-friendly tactical voting tools are advising voters to vote Lib Dem in seats where, based on the 2017 election results, only a Labour candidate could beat the Tory. I can see the case for voting Lib Dem in a Tory-Lib Dem marginal – if it helps to get the Tories out. But in many constituencies, a vote for the Lib Dems is in effect a vote for the Conservatives.

We all must do what we can to stop the Tories. But if you’re living in a seat where it looks as though a Labour candidate could beat a Conservative, please vote Labour. There have been times I have been frustrated with Jeremy Corbyn, but a Labour government is our only real hope of progressive change, not just for young people, but for everyone.

The policies the Labour party is offering would be transformative. Meanwhile, the Lib Dems seem to loathe Corbyn’s politics more than they loathe those of the Conservatives, despite the fact Labour is offering exactly what they’ve been asking for – a second referendum. Jo Swinson is noticeably more energised in attacking Corbyn than she is Boris Johnson.

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Her party is not focused on reversing generational injustice; on the contrary, it has enabled it. The Lib Dems – with Swinson as a coalition government minister – were happy to work with the Conservatives to slash benefits, cut social care and play havoc with the health service. Their political conscience only seemed to return when Brexit threatened their world view and their interests. Ideologically, they largely overlap with the vanishing “moderate” wing of the Tories – whose MPs are now defecting to the Lib Dem party. Many of my peers who fell for Cleggmania in 2010 say they’ll never vote Lib Dem again.

Today’s young people deserve better than we got. When I see younger people taking action on climate change, I feel proud. Your vote is powerful. So powerful that university lecturers who encourage students to sign up to vote are facing harassment.

A decade is a long time and also isn’t. I signed on for a bit, got a job, became a writer, got married. Loved ones died and new loved ones were born. Many of us are still in debt. Many of us don’t own a house. That’s life. But life intertwines with politics. And on 12 December you have a choice that could shape yours, for better or for worse.

• Rhiannon Lucy Cosslett is a Guardian columnist