ALEX Salmond has gone to great lengths to enhance Scotland's ties with China, but even he has outdone himself this time.

He allowed his Chinese interpreter to get married for free at Bute House – the First Minister's publicly-funded Georgian mansion residence in Edinburgh's elegant Charlotte Square – and even paid for the catering.

The generosity, described as "remarkable" by Labour, is believed to have personally cost the SNP leader thousands of pounds.

Like his predecessor Jack McConnell, Salmond has been determined to explore the opportunities for Scotland in the vast Chinese market.

He has visited the superpower several times since becoming First Minister. But not being fluent in Mandarin, Salmond has relied upon an interpreter to get his message across to the Chinese government.

Isabel Hui Liu, who studied for a doctorate at Heriot-Watt University, was hired by the Scottish Government to ensure the First Minister's message was not lost in translation.

She has helped him overcome language barriers and even travelled to China with his administration.

Hui Liu is in demand elsewhere. A biography notes her clients include the Royal Bank of Scotland, the Bank of China, and the Consulate of the People's Republic of China.

Her professional success has been accompanied by personal happiness: last month, she got married.

The Sunday Herald then learned that Hui Liu and her groom were allowed to use Bute House in Edinburgh for their humanist ceremony.

A lavish reception also took place in the SNP Government leader's grace-and-favour home.

A Government spokesperson said that the First Minister had hosted the wedding. She added that the "warm, personal gesture" had been funded by the SNP leader, who "met all costs" himself.

One Government source said the First Minister and his wife, Moira were "very fond" of the interpreter.

Salmond's act of generosity saved the couple a lot of money. Given that the average wedding costs around £20,000, having the First Minister pick up the banqueting tab in a venue that came free was helpful.

While Bute House is not marketed as a wedding venue, Salmond can use the property for personal purposes under the Government's ministerial code.

Section 7.2 of the document makes clear that where "personal events" take place in Bute House, "no cost" should fall on the public purse.

A row blew up earlier this year after it emerged that Salmond hosted lottery winners Colin and Chris Weir at Bute House. Days later, the couple donated £1 million to the SNP.

An investigation found that Salmond complied with the Ministerial code, as the tea and biscuits provided had come from his own resources.

The First Minister is well known for his munificence towards friends. He famously treated his dentist to a seat in the royal box at the Edinburgh Military Tattoo.

Willie Rennie, the Scottish Liberal Democrat leader, said: "It's a really nice touch for someone who clearly means a lot to the First Minister. However, I suspect if I was to learn Mandarin the First Minister wouldn't even pay for my birthday party."

A Scottish Labour spokesman said: "This is remarkable generosity from the First Minister and it's nice to see an occasion where Alex Salmond upholds the values of marriage in Bute House."

A Scottish Government spokesperson said: "The First Minister was delighted to host a wedding ceremony at Bute House – which was a personal event. The bride has performed unstinting service to the Scottish Government as a Chinese interpreter.

"She had no relatives in Scotland, and this was a warm, personal gesture by the First Minister who met all costs of the event, including catering, himself – no Government staff costs were involved."