Jack McConnell will become Britain's next High Commissioner to Malawi in recognition of the work he has done on strengthening the links between Scotland and the African nation.

Gordon Brown, the Prime Minister, announced yesterday that he wanted the former First Minister to replace the current High Commissioner, Richard Wildash, when the diplomat leaves that post in 2009.

It is expected that Mr McConnell will then have to stand down as MSP for Motherwell and Wishaw, sparking a by-election around the time the next Westminster election is expected.

The job would require him to be resident in Malawi and comes with a house. The move also raises questions about the future of his wife, Bridget, as a senior official at Glasgow City Council.

If Glasgow wins the bid to host to the 2014 Commonwealth Games, it is thought she may stay in Scotland.

When asked whether Mrs McConnell will join her husband when he moves to Malawi, a spokesman for Mr McConnell said: "That's the likelihood, but it's a few years off and it depends what Bridget has got on her plate."

News of Mr McConnell's appointment as High Commissioner came shortly after he announced he was resigning as Scottish Labour leader and would be taking up a role with the Clinton Hunter Development Initiative (CHDI) - set up by former US President Bill Clinton and Scottish philanthropist Sir Tom Hunter - which will see him exploring ways of improving educational opportunities in Malawi and Rwanda.

In his resignation statement, Mr McConnell said his one regret after nearly six years as Scottish Labour leader is that he did not have the opportunity to implement his manifesto's education plans. He set out the ways in which he believes his time as first minister made Scotland "a far better place because we took bold action".

He said he felt pride, even after the disappointment of losing office, with policies showing continuing progress on population growth, higher employment, and anti-sectarianism. "All my life I've wanted a Scottish Parliament and a chance to change Scotland," he said. "I'm pleased to have made my contribution to that."

Of his future work in Africa, he added: "I am very excited to bring together my other two life-long passions, education to release human potential and ending poverty in Africa. In fact, I can't wait to get started. It is time for the rest of my life to begin".

Mr McConnell described the offer of the High Commissioner post as "very special" and said he was "delighted" to accept. "I'm sure, in addition to representing the UK government there, it would be a real opportunity to further enhance the relationship between Scotland and Malawi and to support those thousands of Scots that are now involved in partnerships with Malawian organisations and people from Malawi on the ground," he said.

Under Mr McConnell's leadership, the Scottish Executive gave millions of pounds in aid to support health and educational projects in Malawi.

The former first minister also visited the country two years ago and was ordained with the powers of an African chief, symbolised by the presentation of a carved mahogany "stick of authority".

It was bestowed on him by the chairman of the Henry Henderson School, which was founded by Scottish missionaries in the 19th century.

Gordon Brown said it was Mr McConnell's desire to make a difference in Africa which made him an ideal choice for the post of British High Commissioner to Malawi.

The Prime Minister said: "I know (Jack McConnell) cares passionately about two of the greatest issues of inter-national development - the relief of poverty and the provision of education. I believe he will make an excellent representative of the United Kingdom government in Malawi."

The UK government is currently the largest aid donor to Malawi, providing more than £60m annually, making Mr McConnell's post particularly significant among British diplomats in the capital, Lilongwe.

The Tories responded that Gordon Brown's decision to appoint a politician to the High Commission was a discourtesy to Malawi. Spokesman David McLetchie said: "Jack McConnell is well suited to fill this role given his deep interest in Malawi, but the rush to make this announcement shows that Gordon Brown has chosen to treat the post of High Commissioner to Malawi as a political bauble to be traded for the convenience of the Labour Party".

The appointment was greeted with disappointment by the FDA - the union representing all grades in the Diplomatic Service.

It said that it represented a "worrying trend in political appointments to diplomatic posts", as it followed the appointments of former Scottish secretary Helen Liddell and former chief secretary to the Treasury Paul Boateng to the posts of High Commissioner to, respectively, Australia and South Africa.

Ms Liddell caused a stir earlier this year when she claimed the Iraq conflict had never been part of the war on terror. This embarrassed the Australian government who had justified the country's involvement in Iraq, by claiming it was the frontline of the war on terror.

FDA spokesperson Paul Whiteman said: "The FDA has assiduously campaigned for appointments to be made on the basis of merit following a process of open competition. We believe that this is the only way to avoid accusations of cronyism.

"The government is very keen for top jobs to be open to candidates from outside the civil service and we welcome the diversity that openness brings. However, such appointments can only be seen to be fair if there is open competition between internal and external candidates."

Before taking up that post, the former Scottish Labour leader will carry out his work with the CHDI on a voluntary basis and yesterday said he was excited by the "fantastic opportunity" it offered.

His appointment was approved by the board last week, and Mr McConnell was in France last Friday to finalise arrangements with Sir Tom. He said: "I just can't tell you how delighted I am to announce that I have accepted an offer to lead, on behalf of the CHDI, their work in Malawi and Rwanda."

It is understood that Mr McConnell's role will see him examining successful education projects throughout Europe as well as India to see how they could be introduced in Malawi and Rwanda.

He insisted yesterday that he will be able to carry out most of the work from Scotland, so it will not interfere with his work as an MSP.

Mr McConnell worked closely with Sir Tom Hunter, both in Malawi and Scotland, throughout his time as first minister, and met Bill Clinton when he gave a lecture in Glasgow last year. Next month in New York, he is to attend the ex-president's annual summit on international development issues.

Sir Tom said: "Jack's credentials in addressing this huge challenge require no explanation, it's now all about rolling up the sleeves and getting on with assisting us and our government partners in defining a sustainable, scalable and affordable solution to the challenges Rwanda and Malawi face in education."

Mr McConnell is also expected to be awarded a seat in House of Lords later this year or early next, however there was no comment on that yesterday.

Alex Salmond, who replaced Mr McConnell as First Minister, said the smoking ban and the link with Malawi had helped make Scotland a better place, they were "substantial achievements", and he offered "every good wish for the future".