The opening stages of the great Labour post-mortem were pretty predictable. All those tired old New Labour figures came out the woodwork saying they'd been right all along and Ed Miliband was punished for being too left wing. Their opponents replied that shifting to the right hardly seemed the right way to address the party's total destruction in Scotland.

Neither is right, but both sides have a point. Surely Scotland proves that Labour needs to reconnect to its left-wing roots. The confident, social democratic, anti-austerity message of Nicola Sturgeon was embraced with open arms by an electorate which felt Labour had become Tory-lite.

On the other hand, perhaps figures like John Reid were not being so foolish when they suggested Labour needed a stronger message on immigration and 'aspiration' – that counter-intuitive code word for getting the poor to vote against their economic interests. After all, the extent of the Ukip vote suggests that it came at the expense of Labour. Ukip came second in Hartlepool and was up 18-points in Ed Miliband's own Doncaster North. It won between 20% and 30% of the vote in Labour strongholds like Heywood and Middleton, Barking, Dagenham and Rainham, Houghton and Sunderland South, and West Bromwich East. In Morley and Outwood, Ed Balls would have stayed in place if the he could have funnelled the collapsed Lib Dem vote towards himself, instead of allowing it to go Ukip. The Ukip vote there was up 13.4%, providing 7,951 votes in a seat where just 422 decided it.

Miliband's vague social justice message – of a fair deal for working families - was formulated because it needed to stretch itself across such disparate political constituencies. That plainly did not work. But there is little reason to think that plumping for one side or the other would do any better. Labour can no more afford to permanently lose Scotland than it can its industrial base.

What would the #GE2015 results have looked like under PR? http://t.co/JcraZLzq7f pic.twitter.com/k86fqqJa8k — BBC News Graphics (@BBCNewsGraphics) May 9, 2015

And without Scotland, it really is difficult to see Labour competing for a majority again. It now has a 56 seat deficiency in Scotland. The Tories will implement boundary reform as one of their first actions, making it at least 20 seats harder for Labour to beat them. That's an in-built 75 seat handicap, one which can’t really be curtailed and which anyway should not be. For Labour to turn its back on Scotland and the demands north of the border would be to condemn itself to precisely the sort of Tory-lite message its former supporters accuse it of.

But Blairism isn’t just strategically wrong, it is also uniquely unsuited to the problems the Labour party now faces. This election was not won by the Conservatives as a battle of ideas. It was lost by Labour because of a fragmentation of its vote. Labour voters migrated to the SNP and Ukip. Blairism was based on the assumption that Labour had a monopoly hold on its voters. This allowed him to encroach far into enemy territory – triangulation, they called it – attacking the Tories from the right on law and order or welfare and playing merry hell with them. They could do this, much to the dismay of their core supporters, because they had nowhere to go. New Labour had many messages for the middle class, but it only ever had one for the working class: Vote Labour or get the Tories.

Now they do have somewhere to go. Scottish voters can opt for the SNP, northern voters who never recovered from the death of the industrial base and view immigration as a threat can opt for Ukip.

Blairism was a response to a different problem at a different time. Its adherents now – the John Reids and Jonathan Powells of the world – are as dated as they thought the trade unionists in the party were in their own day. To a man with a hammer, every problem looks like a nail.

Increase in Ukip's share of the vote, 2010-2015, by region #GE2015 ---> pic.twitter.com/HeykC5r0PM — Matthew Goodwin (@GoodwinMJ) May 9, 2015

Furthermore, the proposition that Miliband was running on a particularly left wing platform is laughable, unless a tax on houses over £2 million or the end of non-dom status are now considered Stalinist. These policies were perfectly popular (although admittedly, we're all a little of wary of polls right now). Labour called for the Office of Budget Responsibility to check its manifesto and centred the launch event on deficit reduction. This wasn't some drift to the left. It was a modestly centre-left programme full of policies the public had been shown to support. The minor criticism of monopoly capitalism and media ownership were not just modest, but also popular.

Blairism will prove an attractive siren song for Labour supporters because it offers clear answers which have previously been shown to win elections. Simple answers will be seductive when contemplating a problem as big as trying to get apparently left wing Scots and apparently right wing Ukip supporters to back a single party.

But the right/left terminology is not useful in how to attract these voters. Reid wants Labour to talk about immigration, but being positive about immigration has done nothing to damage the SNP. Is that because the Scots are post-national champions of diversity? Absolutely not. Research commissioned by the BBC found they were exactly as critical as other Brits, with 49% wanting less immigration - exactly the same proportion as across the UK.

Do we really think Ukip voters in northern industrial towns like the low-tax, pro-business message Ukip candidates – many of them former Tories – promote? Or Farage's believe in a privately-run NHS, which he so conveniently put aside for the election? Plainly not.

This is not a policy problem. It is not even a presentational or an ideological problem. It is deeper than that. It is about believing people will stand up for you. The reason Labour voters are flocking to Ukip and the SNP is because they believe they will fight for them. That is the overwhelming driving force of Alex Salmond's and Nicola Sturgeon's movement: the election of a party which voters believe will fight their corner. That's why all criticism of the SNP is water off a duck's back. That's why Ukip can run a right wing agenda in left-wing heartlands – because voters believe they'll stand up for them.

Salmond, Sturgeon and Farage use simple, easily understood language. They do not rely on focus-group approved terminology or lines to take. They have simple ideas – separate Scotland, pull out of the EU – which they express in the language of ordinary people. They are not acting. They are arguing. The public can tell the difference.

Remarkable, instructive map of 2nd places: pic.twitter.com/fptt2JfdWt — amol rajan (@amolrajan) May 8, 2015

The process of creating that sort of proposition is bottom-up. It cannot start with the leader. It has to start at the local level, by becoming a grass-roots, open, democratic party. The sabotage of the party's internal democracy succeeded in making it more professional but disconnected it from its support.

In Scotland, Labour took voters for granted. In the areas of Labour-run councils in England, the lack of viable opposition made the party complacent and lazy.

This was always a problem, but it became much worse under Blair. The idea of encroaching into enemy territory because your own supporters have nowhere else to go is at the heart of the hollowing out of Labour. It is part of the reason for the disillusionment which the party is now paying the price for. And now that people do have somewhere else to go, they're going.

The sad irony is that Blairism is being proposed as a solution for a problem which it itself helped create.