I’m angry that there’s going to be a referendum on Britain’s EU membership.

Angry on a personal level because I was looking forward to a break after campaigning for the May local elections and now I will have to head out on the doorstep for another month and a half campaigning in a poll I would rather wasn’t happening.

Angry with the Tories for using a referendum to resolve their own irreconcilable differences over an issue they seem far more exercised about than resolving the far more pressing economic challenges and social inequality facing the country.

Angry with David Cameron for exaggerating what he could achieve in negotiations so the rather good deal he achieved looks feeble compared to the hype.

Angry with Boris Johnson for putting his ambition to lead the Tory Party above the national interest.

Angry with Labour’s own record in Government for having undermined support for EU membership by allowing free movement to work here to the citizens of the new Eastern European accession states earlier than we had to, so that the politically toxic issue of immigration has become bundled up with the EU as one topic for many voters.

Angry with the political elite at EU level, whether that’s the Council, Commission or MEPs, for dismally failing to create or articulate a Europe with popular appeal, so that what was once one of the most idealistic and passionate causes in international politics has become a technocratic bore-fest of regulation if you live in northern Europe, and a mechanism for externally imposed permanent austerity if you live on the Mediterranean.

Angry with Labour Party members who are more united in their enthusiasm for Europe than any other issue (81% support staying in the EU according to this week’s YouGov poll) but elected as party leader one of Labour’s most Eurosceptic MPs, which means we are not well-placed to lead the “In” campaign.

Angry for my country that a decision of profound importance, which will affect millions of jobs and possibly have an existential impact on the future of the UK as a United Kingdom, is being taken for all the wrong reasons with a level of public knowledge of what the EU really does for us that is pitiful, and a media that is likely to drag the campaign down to the lowest common denominator of xenophobic ignorance.

As a young political activist I used to call myself a federalist and believe in ever closer political union of the EU.

I don’t have that vision any more. As I’ve got older the lack of any unifying progressive political ambition across the European countries about the kind of shared society they would want to create if they did become closer together constitutionally has pushed me towards a position that is more about trying to create a social democratic country here in the UK (even that seems a long way off) than trying to create social democracy across a union of 28 member states.

When I was younger I naively believed that nation states were destined to become a historical irrelevance. But I’ve come to see that there is still a huge value in nation states – states that are bound by a shared culture and sense of national identity as well as being a political entity. Nation states have a democratic political legitimacy because of the shared cultural identity of their citizens that the EU will never have.

But despite this grumpiness and middle-aged disillusion with the European ideal I will be fighting tooth and nail for an “Remain” win in the referendum.

Because the Brexit alternative is tantamount to national economic and political suicide.

I do not believe that Scotland would stay in the UK if the UK was not in the EU. And then we would be a much-diminished rump state with electoral maths that would suggest almost permanent Tory rule.

I do not believe that Britain would be taken as seriously in world diplomacy if we were not in the EU. The USA would look even more to Germany as its main European partner. Our seat on the UN Security Council would be called into question. Our participation in pan-European defence technology initiatives like Eurofighter would look wobbly when the next generation of them is considered. The EU gives us a seat at the top table in trade talks by making us part of one of the biggest global economic blocs.

Much as the mass immigration from Europe of the last decade and a bit may have been too fast and bounced past the public undemocratically, now that it has happened I do not think we can undo it without causing immense economic disruption and personal distress to good people who came here in good faith and are making a hugely positive contribution to our country.

I don’t see major European companies like BMW in Oxford where I live and Airbus in North Wales, which are huge investors and employers in the UK, picking British factories over continental ones for new projects if we were not in the EU. Nor do I see multinationals like Nissan in Sunderland continuing to invest in the UK if it is not the gateway into a single EU market.

And I fear that future Tory governments would further attack workplace rights if they were not bound by basic social standards agreed at EU level. Membership of the EU gives us some scope, however limited, for resisting at a transnational level the worst social impacts of globalisation.

And for all that the current shape of the EU is deeply uninspiring and hardly dynamic, the alternative model, a Europe of 28 squabbling small nations, would be irrelevant in the face of emerging global economic powers like China, Russia, Brazil and India.

And however flawed, an organisation that means that France and Germany now settle their differences in committee rooms in Brussels, not on the battlefield, has to be a project worth staying part of.

This is probably the most important vote I will cast in my lifetime, and the most important campaign I will ever be part of. If we win, it may fade from memory, but if we lose, we will be dealing with the negative consequences for generations.

We need the vast majority of Labour Party members and activists who support the EU to throw their weight fully into winning this referendum, whether it is youthful idealists inspiring their fellow idealists to turn out, or jaded sceptical realists like me persuading other jaded sceptics that the EU is the only realistic viable future for the UK.