Malcolm Offord has refused point blank to publish his tax returns after being challenged by John Swinney.

Reform UK’s leader in Scotland reacted angrily when asked about his tax affairs on Wednesday, telling the Mail: ‘Mind your own bloody business.’

It followed the Greenock-born millionaire revealing on the STV leaders’ debate that he owns ‘six houses, five cars and six boats’ and has paid £45 million in tax over 40 years.

He later said he wanted to start a public conversation about creating wealth in Scotland.

He also confirmed five of his houses are in the UK and the other is in South Africa.

A recent public record shows a £670,000 home in Lord Offord’s name near Cape Town.

Asked if the houses all had boats attached, he joked: ‘Well if you’ve got a house, you need to have a boat, right? You can never have enough boats.’

Mr Swinney said Lord Offord had been ‘tone deaf’ on TV given the cost-of-living crisis.

Campaigning in Edinburgh, the First Minster said: ‘I certainly thought it was tone deaf. Setting out an individual’s personal wealth and using that at a time when people are really facing acute hardship, when they literally cannot afford a decent shop - which is why I’m bringing forward the affordable price cap proposals - was an example of how completely and utterly out of touch Reform are with the reality of people’s lives.’

Asked if Lord Offord should now publish his tax returns, he said: ‘I’d be very happy to publish my tax returns at any stage if that would be viewed to be helpful.

‘My tax returns are fundamentally not interesting at all but I’m sure from what Lord Offord said there could be more than likely a feeding frenzy over his tax returns.’

Mr Swinney said he owns one house, one car and no boats.

Asked if he thought Lord Offord was ‘bragging’ about his wealth on Tuesday, despite him insisting he wasn’t, the FM said: ‘I think he was, yes.’

Asked if he would publish his tax return as he visited Torness nuclear power plant in East Lothian, Lord Offord told the Mail: ‘No. I’m not publishing my tax returns. I’ve told you what I’ve paid in tax over my lifetime. I’m not lying about it. I’m not publishing my taxes. End of.’

The millionaire yachtsman also objected to being asked how much he had earned to pay £45million in tax, which would reveal his effective tax rate.

‘Mind your own bloody business,’ he snapped. ‘I’ve told you what I’ve paid in tax. I’m not telling you anything more.’

The financier was a member of a London-based private equity firm whose managers would have been able to pay capital gains tax on shares of profit rather than income tax, meaning they might pay a lower rate than the office cleaners.

Asked if he had been paying capital gains tax, Lord Offord said: ‘The door’s not opening any further. I made that statement because I want people in Scotland to have a conversation about whether they want people to be successful.

‘I want people in Scotland to have a conversation in the pub about, Is it a good thing for people to make money? Because if they make money, it would appear that they pay a lot of tax not pay for a lot of public services.

‘And I want people to start talking about the Greens policy of giving everything away for free, and how they’re going to pay for that.’

Scottish Tory leader Russell Findlay said: ‘As Scotland’s party of aspiration, business and hard work, we don’t sneer at success. But voters struggling with the cost of living might find it jarring to hear Lord Offord bragging about his vast wealth.’

Scottish Labour leader Anas Sarwar added: ‘I’ve published my tax returns before and I’m happy to do so again.

‘I’m all for success - I come from an entrepreneurial family. But Malcolm Offord is pretending to be a great champion of working class communities.’

Scottish Liberal Democrat leader Alex Cole-Hamilton said: ‘There is a place for millionaires in politics but he rammed his success down the throats of ordinary working people.’