Chris Martin: Senior civil servant who was right-hand man to Gordon Brown at the Treasury and David Cameron at No 10

The qualities of a Prime Minister's Principal Private Secretary are enduring: discretion, diligence, brilliance, and a generous spirit - and Chris Martin, the equal of many an illustrious predecessor in the post, stood out as a man of his own time. Much younger than many past holders of the post when appointed at the age of 38 in 2011, Martin was an accomplished cook and a marathon runner, and enjoyed attending pop concerts.

Opposite sorts appreciated his talents, including both Gordon Brown, to whom Martin was Press Secretary hen he was Chancellor, and his last boss, the present Prime Minister David Cameron.

"I've never seen him cross," one Parliamentary friend recalled. It was Martin who prepared Cameron for his appearance before the Leveson inquiry in June 2012, at which the Prime Minister faced awkward questions about his relationship with journalists allegedly implicated in illegal phone-hacking, and about his handling of the government's approach to a bid by Rupert Murdoch's News Corporation to take over the broadcaster BSkyB.

Later the same year the unflappable Martin helped Cameron field questions about "Plebgate", in which the then Conservative Chief Whip Andrew Mitchell was embroiled in a dispute with a police officer at the gates of Downing Street. Martin was also one of what has been described as the "Golden Triangle" of senior officials to whom government and the Queen would have had to turn, should Scotland, in the referendum of September 2014, have voted for independence from the UK. The others were the Queen's Private Secretary, Sir Christopher Geidt, and the Cabinet Secretary and Head of the Civil Service Sir Jeremy Heywood.

It was a mark of royal appreciation of his role that Martin was appointed CVO a few days before his death; he had been made CB in 2014. Martin had worked his way to the top of the Whitehall machine by way of the Treasury, where he was quickly marked out as star material by being given a Private Secretary posting, to the Financial Secretary to the Treasury, in 1999, only three years after he joined in 1996. He worked first for Barbara Roche, then from July that year Stephen Timms, staying until January 2001.

He moved on to principal grade at the Treasury's productivity team, and the expertise he gleaned there took him for nine months to the then-financially troubled London borough of Hackney as performance improvement manager, reporting to the borough's Assistant Chief Executive. Two deputy director posts followed, at general expenditure policy and as head of the productivity team.

From April 2006 he became Press Secretary to the Chancellor of the Exchequer, Gordon Brown, whose turbulent personality he put up with for a year and two months before Alistair Darling took over in June 2007 on Brown's becoming Prime Minister in succession to Tony Blair. Martin became the Treasury's interim director, corporate services. In December 2007 he moved on to be the Treasury's director, public services, a post he would hold for three years, in charge of energy and environment policy, as well as public spending policy on justice, intelligence, defence, home affairs, and culture and diplomacy.

Among the many House of Commons Treasury Select Committee hearings at which he gave evidence was one in March 2008 when, introduced as having particular responsibility for the environment, he answered questions on the soaring cost of fuel, and how users might be helped. "On the discussions with the energy companies we certainly hope that we will be able to bring something forward for the winter following the winter coming," he told committee member and Labour MP Nick Ainger.

In 2010 he was appointed director, national security secretariat in the Cabinet Office. "You would be jealous of any minister who had him as an adviser", one Member of Parliament said of Martin. He is remembered as being extremely professional, and to have excelled at helping anyone wishing to think a matter through.

He enjoyed research, and carried his zest for discovery from work into his leisure hours, where he loved to invent interesting feasts for friends using the best possible ingredients. "He was a phenomenal cook, with a natural skill," one friend said. "I would never have dared to cook for him. He could rustle up anything - he was an exceptional host."

Martin could explain everything about music, it is remembered, and one of the concerts he went to was a comeback performance at Alexandra Palace in north London, in March 2013 of the "decadent" mid-1990s pop group Suede. He also supported Arsenal FC.

He was a loyal friend whose acquaintance went back to his time at Bristol University between 1991 and 1996. He began by studying physics but switched to politics, obtaining a BSc Hons in physics and a BSc in politics. His earlier education was at a comprehensive.

In 2005 he married Christina Scott, a fellow Treasury civil servant, but they separated in 2012. For a time afterwards both worked at the Cabinet Office. In 2013 she was appointed Governor of the British overseas territory of Anguilla in the Leeward Islands. In 2015 Martin married the BBC journalist, Zoe Conway. There were no children from either marriage.

Martin's illness, a sarcoma, was diagnosed in 2013 but while in remission he was well enough to continue a tradition he and his brother, Rich, a leukaemia sufferer, had established together, of running marathons for charity. Their parents, Peter and Gwenda Martin, joined many friends to sponsor them, and Chris Martin raised more than £40,000 for the Anthony Nolan Trust and other causes – latterly, in his fourth London Marathon, in 2015, for Sarcoma UK.

Speaking in the House of Commons, David Cameron paid tribute to Martin, who had the title as well as Principal Private Secretary, of Director General, 10 Downing Street. He was, said the Prime Minister, "someone between a father and a brother to all of us", and "one of the most loyal, hard-working, dedicated public servants I have ever come across".

Christopher Jon Martin, civil servant: born West Bromwich 15 May 1973; CB 2014, CVO 2015; married 2005 Christina Scott (marriage dissolved), 2015 Zoe Conway; died London 25 November 2015.