The Sun Ed Miliband front page
Coverage such as the Sun's eve-of-election spread gave Miliband and Labour little chance.

It's been a long day. I got to bed about one o'clock and was up at six to see the denouement. I think by the time I got to bed it was clear the Tories were on course to win, but even at that stage no-one predicted the margin; they were on about 315 seats at that stage and ended up with 331.

The defeat is hard to take after such a long and tough campaign. I personally gave the Labour Party £1.6m in shares in 2011, and some additional money earlier this year. But I don't regret the investment; I've been a long-time supporter and you've got to take the rough with the smooth, and stick at it.

Was the campaign responsible for Labour's defeat? No, I think the campaign was itself was fought pretty well, there was little division, everyone stuck to the policies that had been promulgated, and the organisation was probably better than the Conservatives.

Ed Miliband
Labour's campaign was fine - it was slick, tight and unified.Oli Scarff/AFP/Getty

I think the weakness stretch further back, and there were two that were absolutely critical: firstly the ratings of the leader - Miliband's weren't as good as Cameron - and secondly on the economy, where Labour has traIlled since 2008.

I also think the Labour campaign was blighted by two key issues, largely beyond his control. The first was the timing of the election: the Coalition policy of retrenchment was a terrible mistake but the economy has bounced back just about in time to push Cameron back into office. That was something Labour couldn't do anything about.

Then there is the way the right-wing press hounded and insulted Miliband. The Conservatives were vicious in the way they consistently attacked the Labour leader, and the right-wing media lapped this up, and really demonised him. In fact, you can say that the Tories' victory is also a victory for that agenda, peddled in the Telegraph, the Mail and their ilk.

When people were more exposed to Miliband, during the debates, they realised his public image was nothing more than a caricature, and his ratings shot up. Miliband proved he was good at picking up on issues that resonated with the public, like bankers' bonuses. But it came too late; the media hounding had done its job.

Going forward, however, I think the Labour Party has to rethink its strategy. The Ed Miliband approach was to reconnect with the core support, rather than focus on the wider constituency, as Tony Blair did. I think the Labour Party has to revert once to that wider focus, without necessarily going back to Blairism. And they have to win the confidence of British business and Middle England.

I don't have a view on who should be leader, that's for the party to decide. But I do think we need an outgoing leader, that's one of the most important things. Someone with economic credibility, and charisma. Chukka Umunna obviously ticks those boxes and would be a strong contender, but you've also got Andy Burnham and Yvette Cooper.

However they choose, I think the Labour Party has to do a fair bit of soul searching and look at all the policies it's been propounding, and their appeal. This election has been a wake-up call for the party, but now we get the chance to regroup and rebuild with a clean slate.

John Mills is founder of consumer products company JML and a prolific commentator on economics. He runs his own blog, which can be found here.