Today, I've launched Vote Leave Watch, a new grassroots campaign to hold Leave campaigners to account for the promises they made during the EU referendum - and to call them out when they fail to deliver.
During the EU referendum, the Leave campaign accused Remain campaigners like me of engaging in 'Project Fear'. But the truth is that they themselves were peddling 'Project Fantasy'.
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 £350million 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.
These three big claims came alongside daily further pledges. Leaving the EU, apparently, will see more money spent on schools, roads and railways, tax cuts, and cheaper fuel.
52% of the British public relied on many of these promises when deciding how to vote. 48%, including me, had grave reservations about the risks involved and future gains from membership we could sacrifice. The decision has been made, and I respect it totally. But it is vital that the politicians who made these promises are scrutinised and held to account. When we make a pledge, we must expect to be held to account on it.
Yet the backtracking has already begun. Take the famous "£350million a week for the NHS" pledge. Since the referendum result, Nigel Farage has called the result "a mistake". Michael Gove launched his campaign for the Tory leadership by promising to boost the NHS by a mere £100million 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 £350million 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 £350million figure was simply wrong? That it was, as the head of the UK Statistics Authority said repeatedly during the campaign, "misleading"?
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 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.
Chuka Umunna is the Labour MP for Streatham