Profits at the Cloburn Quarry building products operation surged to a five-year high of £5.4m in the latest year, allowing owner Robert Durward to increase donations to the right-wing New Party by more than 50% while taking £1.5m in dividends out of the firm.
Accounts for the Lanarkshire business show the New Party, chaired by the outspoken Durward, received £209,093 from Cloburn Quarry in the year to September, as it continued to be a significant beneficiary of the boom in demand for products such as aggregates and concrete before the credit crunch hit builders.
This boom helped Cloburn increase pre-tax profits by 40%.
Including the latest donations, Cloburn has contributed more than £1m to the New Party's coffers since it was founded by Durward in 2003.
The rise in contributions could herald an increase in campaigning by the party, on its platform of low taxes and minimal regulation on industry. This is combined with hostility to official plans to combat global warming.
Last year, the party backed a Kent school governor, Stewart Dimmock, who made an unsuccessful attempt to get a court to ban Al Gore's film An Inconvenient Truth, which highlights the possible consequences of climate change, from schools in England and Wales.
The party has so far failed to get any MPs or MSPs elected, but its website indicates it hopes to profit from the political difficulties that the Labour government is experiencing if the official opposition does not present a "credible alternative".
In their report included with abbreviated accounts for Cloburn Quarry, filed at Companies House, directors said they were pleased with the development of the company and the results for the year.
The company, which blasts red granite from a quarry operating for more than 100 years near Lanark, supplies products used for making coloured drives and cement. It supplies clients in Europe, North America and Asia.
Pre-tax profits have grown in four out of the last five years, rising from £1.2m in 2003. In the year to September 2006, profits edged down to £3.84m from £3.95m in 2005.
Earnings may come under pressure as a result of the slowdown in markets like property development and housebuilding resulting from the global credit crunch.
However, the 57-year-old Durward was confident enough to take a £1.5m dividend out of the business for the last year, after doing without in the preceding period.
Durward did not return a call to the firm's headquarters.