One of the most interesting narratives of the election campaign has been the suggestion that Britain's business leaders will flee the country en masse if Ed Miliband wins. Some have described it as cast in stone, a fact in waiting; others have suggested it is nothing more more than the hyperbolic ranting of the right-wing press.

I chair quite a few companies, and I advise a few more. Some of the biggest in the land, some of the smallest in the land. And I can say categorically, for certain, that the talk of a Miliband-inspired flight of business talent is no exaggeration. It will definitely happen.

Miliband's speeches may have got slicker over recent months. His delivery is smoother, his body language more confident. He is probably more adept at negotiating a bacon sandwich these days. But the core message remains the same, and business leaders have read it loud and clear. They view Ed Miliband as their worst nightmare since Michael Foot.

It's not a popularity contest. It's about what he believes in. Whether it was Kinnock or Smith, Blair or Brown, even Red Ken Livingstone, they all believed in letting business people make money. And when those people had made their money, there would be a discussion about how much of that money should be handed over to the public purse. But essentially it was an argument about the level of taxation.

This argument is different. This a fundamental dispute about the best way forward for British business. Miliband is an interventionist socialist with a deep conviction about intervening in markets. In other words, he thinks he can run a business better than the businesspeople themselves. He wants to go straight back to the 1970s.

This concept of increasing income tax from 45% to 50% - we all know it'll only raise a couple of hundred million, and it won't cause anyone to leave. Most people affected by the tax will find a way round paying it. But the point is it's emblematic, it's totemic, an example of a wider ideological vindictiveness. As I've said before, it's the mood music.

Imagine you're a headteacher in a really difficult comprehensive school in London. You and your partner bought a house years ago for £300,000, now it's worth £2.5 million, and of course you're going to be paying mansion tax. And your salary of £160,000 a year, every penny of which is hard-earned, is now subject to 50% taxation. You've ceased to be one of Ed Miliband's hard-working families; now you're a rich person who should pay the price. In Ed Miliband's eyes, you're the same as Roman Abramovich.

Have you ever heard Miliband say that profit is a good thing? Have you ever heard him say 'I'm on the side of the biggest companies in this country making loads of money so your pension fund goes up in value, huge amounts of tax are generated and lots of hospitals are built?' You've never heard it. The man has no understanding of business, and he is opposed to it. So therefore the people who create wealth in this country are saying 'this isn't a place I want to be.'

The Sun Ed Miliband front page
Miliband\'s gaffes have provided easy laughs for the tabloids but his lack of business nous is no laughing matter.

This isn't an apologia for the big corporations which make fortunes here and don't give anything back in tax. I think Google, Amazon, Starbucks and the rest are disgraceful. But I belong to a system which says that if it's not illegal, you're allowed to do it. If you think it is wrong, change the law.

George Osborne has already begun efforts to change that law, and rightly. The average businessperson down the road, the person cleaning windows and mending gutters, is just as disgusted as you are about this sort of practice; it's not the sole preserve of Socialists to hate it.

Miliband has never hired anybody, he's never fired anybody. He's never put his mortgage on the line and said 'my family aren't going to have a holiday for two or three years while I build a business.' He wouldn't have a clue about it.

SNP will make Miliband look like a free-market capitalist

The danger of Miliband is magnified by the wildly oscillating tail which will wag his government if Labour are victorious. The spectre of the SNP looms large; in fact, I can't think of anything more damaging than Nicola Sturgeon's party.

When it comes to a Labour-SNP alliance, I think Miliband is telling the truth. He won't do a deal with the SNP. But still, he'll have to rely on them.

Sturgeon said something very telling the other day when she suggested that, if Labour were to put forward a budget in a minority government, her party would be happy to reject it until it was changed to their satisfaction. What she means is 'if you don't do it my way, I won't vote it'. Which means she is going to be in power. Miliband will hide behind the old 'I haven't asked for this' line, but that isn't good enough.

If the SNP have any sniff of power, people will realise they make Ed Miliband look a free market capitalist. They are seriously left-wing. So you would have this constant issue of a man who can't carry England, propped up by a socialist party from Scotland, led by a woman who hasn't even got a seat at Westminster. The ordinary English voter wouldn't stand for it and Miliband would forfeit any legitimacy, which would only weaken domestic and international confidence further.

People might argue that Cameron's EU referendum would pose a bigger risk for British business - specifically, the suggestion that Britain could leave the EU. But I'm certain that, if the British people were to vote themselves out of Europe, there would be a free trade agreement in the morning. Germany sell a million cars a year in Britan; 90% of our trains are made in Dusseldorf. France would know we could make French wine four times more expensive if we wanted. There's no incentive for the European leaders to marginalise us.

Lord Heseltine

'The economy card is critical and central. David Cameron rightly is playing to his strengths.​'

Read Lord Heseltine's take on the campaign here.

I do agree that the two-year delay implicit in Cameron's referendum plan is a danger. If the Conservatives were to win power and hold the referendum in 2017, it would spend the next two years with its eye off the ball, trying to build up a head of steam in favour of staying in, trying to get meaningful reforms from Brussels to present to the British people. Businesses hate uncertainty; they'd rather have bad news than no news.

If I was Cameron and I won the election I'd be trying to shrink that referendum timeframe. I'd be trying to reduce it from 12 months to 24 months, simply because I'd want to kill the corrosive uncertainty.

But when you talk to people in Europe, they're not worried about a Brexit. They're simply stunned by the idea that we're going to throw away our economic recovery by betting on a government which wants to turn the clock back 40 years.

I had dinner the other day with a French banker who said the rest of Europe cannot believe this. He told me 'you've got the most successful economy in the developed world. No inflation, low interest rates, virtually no unemployment and high growth. And you want to change it? The rest of Europe are laughing at you.'

We need to nip this joke in the bud, now. Britain has come a long way since Michael Foot, and we can't let Miliband and the SNP puppet-masters drag us back there.

Lord Digby Jones is one of Britain's most influential business leaders, having served as Director General of the CBI and Minister of State for Trade and Investment. He is now a cross-bench peer in the House of Lords.

In addition to his political role, Lord Jones serves as chairman of Triumph Motorcycles Limited, and holds advisory and non-executive roles in several companies including BP, JCB, Grove Industries and Jaguar Cars. He has also written an acclaimed book entitled Fixing Britain: The Business of Reshaping our Nation.

You can find out more about Lord Jones via his website, or connect with him on Twitter @Digbylj.