THERE is a painting in the boardroom at John Boyle's Hamilton Portfolio which carries a bit more significance than something nice to hang on the wall.

The work was commissioned when the private equity vehicle was founded in 1999 by Mr Boyle and former PricewaterhouseCoopers executive Andrew Lapping.

The large Frank Docherty piece is something of an analogy for how Mr Boyle views Hamilton Portfolio.

It shows a man scattering grain on the ground beside a fruit-bearing tree in a bid to grow more crops.

But behind the farmer is the figure of a white masked soothsayer, which Mr Boyle says is to remind everyone "not to get too big for our boots".

Although now in his sixties, Mr Boyle appears to have lost none of the energy that has made him into one of Scotland's most successful entrepreneurs.

He speaks passionately on subjects ranging from internet security and drug trafficking to holidays, football and the future of Scotland.

On the latter point he is quite clear he is against the possibility of independence.

He said: "I am Scottish. I live here and love the country. But I think it would be an economic and social catastrophe of epic proportions to disengage with England and the Union.

"I think it would unquestionably create uncertainty. If you put a barrier to people you are doing business with that creates problems.

"With our businesses we would have to review whether we stayed here."

The interests in the Hamilton stable are wide with some property funds sitting alongside shareholdings in businesses across a number of industries.

Mr Boyle has taken quite an active role in English printing business Gemini which has been turned round from a six-figure loss to around £500,000 of profit.

There is East Kilbride internet age verification software provider NetIdMe which has clients including British American Tobacco plus others in gambling, online gaming and retail of restricted goods.

Hamilton also has stakes in AIM-listed interactive television gaming NetPlay and maritime communications specialist Software Radio Technology, which has government contracts around Mexico to help stop the flow of illegal drugs.

As well as that, Hamilton and Mr Boyle both have stakes in Glasgow based travel company Minoan Group.

He said: "[Minoan managing director] Duncan Wilson worked for me at Direct Holidays and has been enormously successful since.

"We are very enthusiastic about Minoan and we think it has great prospects. Duncan is doing a good job and it is nice to see a travel company back in Glasgow."

Hamilton also recently sold corporate expenses management business Global Expense to American firm Concur for £14 million.

Mr Boyle says opportunities to invest in companies come about in different ways but there are general rules he and the Hamilton team follow.

He said: "I remember Joe Lewis, the famous financier from the Bahamas, was selling the Sea Shell fish-and-chip restaurant on Edgeware Road [in London].

"He sold it to Rank and I asked him why. He said: 'There's nothing you can prove [with it]. It opens at 11 and closes at 11. There's always a queue and every seat gets filled.

"There is only decline. The business is at its optimum.'

"I remembered that as a lesson to never buy things that don't need much fixing. If you do that then you are just taking an asset and just hoping you can hang on [while it goes well]. We disregard things we know nothing about and we are only interested if we can add value. It has to be something of reasonable size and with reasonable prospects."

While Mr Boyle has had some incredible business highs – not least the £84m sale of Direct Holiday to Airtours – there have been two major lowpoints.

The administration of Motherwell Football Club in 2002 and the collapse of the Zoom airline both play big parts in the public perception of Mr Boyle.

He said Motherwell was a strategic move needed to stem losses and points out the majority of creditors other than him were paid in full.

A move towards fan ownership at Motherwell – with Mr Boyle giving up his shares for nothing – is progressing well and he praises the current board at Fir Park.

Mr Boyle, who also holds an Arsenal season ticket, said: "The whole gambit of [Scottish] football requires a different operational stance than having one owner. People feel so passionate about it.

"Look at the way Rangers supporters stood by their club, it was magnificent.

"But it is moving into a place where the fans need to have their say. It is difficult times for football clubs but I think the Motherwell model is the way forward."

Zoom is described as a "great sadness" which was sunk by an oil price which almost trebled in the summer of 2008 after the airline had taken advice not to hedge its bill.

Mr Boyle said: "It wasn't a failure because we were incompetent, devious or anything like that.

"It was something that would have been a very substantial business. I see blue aeroplanes at the airport and still get a wee bit upset. There is nobody in Zoom could have done any better than they did."

While he still enjoys "getting hands on", Mr Boyle – who retains a shorthand secretary as he cannot type – has no intention of ever going back to being a full-time chief executive.

He adds: "I have a very good team and I am genuinely working a lot less. I get as much holiday as I wish and if I want to take the afternoon off then I do.

"Like every other business the recession has been tough and we have had to get our heads down and make sure we preserve value.

"Nobody has been untouched by what has happened but I think things are getting a wee bit better."