I'm proud of the role Labour activists played in the referendum campaign. Proud of the thousands of members, supporters and trades unionists who went out on the doorstep night after night, taking the message that working people were stronger, safer and better off with the UK in the European Union.
And like so many of us, I'm bitterly disappointed that in the end, it didn't prove to be enough.
The aftermath of the referendum has caused an earthquake in British politics. But it is vital that, no matter what happens over the coming weeks and months, we do not take our eyes of the EU ball as the next Tory prime minister negotiates Brexit in a Government dominated by a Vote Leave agenda.
We must look forward, by assembling a fresh, distinctively Labour case for how our new relationship with Europe the EU should work.
But we mustn't forget what has happened over the last few months either. That's why today I have launched Vote Leave Watch -- a new campaign to make sure the promises and claims the Leave campaigners made to the British people are not forgotten and that we hold them to account for them. We mustn't forget the wild claims and impossible promises made by Tory Leavers like Andrea Leadsom, Michael Gove and Boris Johnson.
They claimed, repeatedly, that leaving the EU would do no damage whatsoever to the British economy. They drove a huge red bus around the country with the words "We send the EU £350m a week, let's fund the NHS instead" emblazoned down the side. And they promised to negotiate an exit deal with the EU based on "free trade and friendly co-operation" which would allow Britain, unlike Norway, Switzerland or Iceland, to simultaneously restrict immigration from Europe.
Yet the backtracking has already begun. Take the famous "£350m a week for the NHS" pledge. Since the referendum result, Nigel Farage has called this promise "a mistake". Michael Gove launched his campaign for the Tory leadership by promising to boost the NHS by a mere £100m a week extra.
Chris Grayling airily said it was nothing more than "an aspiration", while Iain Duncan Smith claimed he "never said" that the full £350m would be spent on the health service.
Almost the minute the polls closed on June 23rd, the Brexit battlebus went into a screeching u-turn. Could it be because they know that the £350m figure was simply wrong? That it was, as the head of the UK Statistics Authority said repeatedly during the campaign, "misleading"?
This change of heart demonstrated just how little the Tory Leavers care about our NHS. For them, it was always a cynical campaign ploy, and never a matter of conviction.
On the economy, the Leavers' shrieks about "Project Fear" have never felt so hollow. With the pound hitting its lowest level since 1985, global giants like Visa talking about shipping jobs abroad, and business pessimism doubling, it is clear their claim that Brexit would boost the economy was entirely false.
The Tory Leavers want us all to forget about the things they said during the campaign. For all voters -- Leave or Remain -- it is vital that this does not happen. At Vote Leave Watch, we will spend every day scrutinising Boris, Gove, Andrea Leadsom and the rest of them, and letting you know if they aren't delivering. So join us today by signing up at VoteLeaveWatch.org.uk, following us on Twitter at @VoteLeaveWatch and Like us on Facebook.