David Cameron’s surprise intervention shows just how worried Remain are

Using the door of Downing Street in this way is a tactic borne out of desperation.

In a statement designed to win over elderly voters and reinforce fears about the economic consequence of a Leave vote in Thursday’s referendum, Cameron spoke outside 10 Downing Street; the first example in modern times of a prime minister using the paraphernalia of his office in election time, though the podium appeared without Whitehall’s branding and was paid for by Britain Stronger in Europe, not the government.

Although this latest warning may be enough to avert a Brexit vote on 23 June, it has dramatically brought forward his “use by” date – he hit his “Best Before” date the second he pre-announced his departure during the 2015 election campaign – as if Remain do go on to win from here, it will only further enflame the narrative among his Conservative critics that Cameron behaved dishonourably during the referendum campaign.

But will it work? Cameron – and the people around him – are not naive. They know that by making this statement in front of Downing Street, they’ve foregone any slim hope of reuniting the party after a Remain vote. (One problem is that, rightly or wrongly, most Tory MPs believe that there are no circumstances under which Jeremy Corbyn can defeat them in 2020, making unity a low priority.)

It attests to the worry in Downing Street and the Remain camp generally that, despite a series of slightly more favourable polls this week, things in the country are not going well. Although the message that Downing Street were looking at polls putting them ahead by ten points was well-briefed at the weekend, the message from out in the country – with the exception of England’s big cities and Scotland – is almost uniformly bleak for Remain.

Privately, there is a feeling that the suspension of campaigning hurt Remain not Leave, as it meant that the campaign had to forego its biggest gun: a warning from Mark Carney, the governor of the Bank of England, that a Brexit vote would mean an interest rate hike. Very few privately share the bullishness about the outcome that the betting markets – which still make Remain the overwhelming favourite – or the currency markets – which are rebounding following a series of good polls – indicate.

Cameron’s fear is that this is only the first sombre statement about Britain’s relationship with Europe that he’ll need to make this week. He’ll take a shortened political shelf-life after a Remain victory over going down in history as the PM who took Britain out of the European Union by accident.