For those who did not know him or know of his works, the response to the death of the British socialist, journalist and writer, Paul Foot, may seem remarkable. Front-page news on most national papers, a full-page obituary in the Times, a five minute item on the BBC’s flagship current affairs programme. This was more than could be explained simply by the tragic suddenness of his death or the fact that journalists tend to write more about their own than others.

Paul’s roster of public achievement is impressive: numerous successful campaigns against miscarriages of justice, millions of words in newspaper and magazine columns in which he hunted out corruption, injustice and hypocrisy – nearly always with a coruscating wit – and a record as a brilliant public speaker. But somehow simply listing this does not capture the man. Many who achieved this would become aware of their importance, their status, their power, even. But Paul was not like this.

He was completely lacking in pretension, pomposity or personal vanity. He never rested on his laurels, he never presumed he knew everything and he never begrudged giving others help and encouragement. Always capable of telling a story against himself, always interested in new ideas and always attuned to the strengths of his opponents, Paul’s integrity and humanity was what drew people to him, even those with whom he disagreed. He was, justifiably, an immensely popular person.

Paul came from an impeccable upper middle-class background – he was educated at a leading private school and his father and three uncles were all major public figures – but for nearly all of his adult life Paul was a socialist. Not just any old socialist, not a member of the Labour Party, but a member of the (Trotskyist) Socialist Workers Party. And not just in his youth – but until the day he died. This, together with the fact that he was such a successful journalist, has provoked some to minimise his socialism – to dismiss it as an upper-class romanticism for the working class, or to mock it as “Bollinger socialism” (a socialist who may or may not drink champagne, but more damningly, one who does not take their socialism seriously).

But, again, this is to misunderstand the man. Socialism was central to what Paul did and how he behaved. It was rage against injustice and passion for a better world which drove him. He wanted to take up the cause of the weak – whether innocent men in jail, pensioners cheated of their pensions or whistle-blowers hounded by their employers – against the strong. And it was his socialism which made him do this well.

He was acutely aware that the proprietors of the newspapers for which he worked, those who he investigated and their supporters in the media would be unforgiving if he made a mistake. His books – among them a demolition of the politics of Labour’s first “modernising” prime minister, Harold Wilson (1968), the exposure of wrongful convictions in the case of the newspaper boy Carl Bridgewater (1986), and Red Shelley (1981) – were meticulously researched.

Paul’s socialism also ran through the centre of his personality. In one sense he was very competitive – he wanted to be the first with a story; he saw no point in journalists recycling material that was already known. But at the same time he was one of the most democratic people I knew – he was generous with his knowledge and his advice and on the two occasions on which we worked together on a television programme he was a great, cooperative partner. I remember he once said that the work of Marx’s he liked most was his 1871 pamphlet on the Paris Commune because what sung out from it was the belief in democracy.

Paul took both work and politics seriously. When he was offered a weekly column in the mass-market Daily Mirror, he took it not just because of the reach it gave him; but also because “only when you have guaranteed space, can you guarantee they will publish what you write.” On public speaking: “Always stand up; don’t read a speech, and take risks with your audience.” It was because he took things seriously, but was not a serious or severe person, that he worked so well. It was impossible to sit down to hear him speak without chuckling, because you knew that shortly his ironic wit would find some material on which to work. His range was amazing: he read widely – literature, poetry, history, modern novels; he loved music, sport, the countryside; and all of this he would bring to his writing.

I knew Paul for thirty years and I don’t think there was a time – whether it was walking on the Cornish coast from St Ives to Zennor, whether it was prowling round secondhand bookshops or sharing a bottle of wine over lunch or dinner – that I was ever bored. Paul was just the most wonderful company, with an insatiable zest for life and curiosity. The last time we met he wanted to know how Britain’s pension crisis could be solved; the last time we talked – just a few days before he died – it was to discuss a television programme which took on the current obsession with “choice” in British political discourse.

Someone once said that the job of the journalist was to “seek out inconvenient facts, champion unpopular causes and insist against all the odds that the virtue of the common people should not be misused.” No one lived up to this challenge more magnificently than Paul Foot.