Bill Alexander commanded the British Battalion of the International Brigades during the Spanish Civil War and was for 30 years until his death a leading member of the veterans’ organisation, the International Brigade Association. In various capacities, from IBA vice-chair to secretary, he was a formidable defender of the honour of his comrades in Spain, doing battle in particular with anyone who used Cold War and anti-communist tropes to denigrate the memory of the 2,500 volunteers from the British Isles who went to Spain – and those 530 of them who gave their lives.

Bill was the author in 1982 of ‘British Volunteers for Liberty’, a book that helped revive interest in the International Brigades as the 50th anniversary of the start of the 1936-39 Spanish Civil War approached. He also chaired the International Brigade Memorial appeal, which raised funds for the unveiling in 1985 of the magnificent memorial to the International Brigades, created by sculptor Ian Walters, on London’s Southbank.

As a follow-up to ‘British Volunteers for Liberty’, he wrote ‘No to Franco: The Struggle Never Stopped, 1939-1975’, telling the story of how International Brigade veterans fulfilled their pledge to the Spanish people that they would continue the fight against Franco on their return to Britain. In 1996 he co-authored, with John Gorman and Colin Williams, ‘Memorials of the Spanish Civil War’.

From 1989-96 Bill was the president of the Marx Memorial library in London, home to an extensive archive of documents and artefacts on the Spanish Civil War and the British response to it.

Bill frequently clashed swords with those who sided with George Orwell’s view of the war in Spain, as expressed in ‘Homage to Catalonia, to criticise the role of communists and the Soviet Union. In ‘George Orwell and Spain’ – a chapter in ‘Inside the Myth’, edited by Christopher Norris – he wrote that Orwell had failed to learn the lessons of Spain, that the priority was to defeat fascism and defend the elected Spanish Popular Front government and not to violently pursue ‘hollow phrase-mongering’ revolutionary goals that threatened the war effort.

Just as dismissive was Bill’s verdict on Ken Loach’s 1995 film ‘Land and Freedom, loosely based on the Orwell memoir. He accused it of presenting a narrow and partisan view of the war that exaggerated the role of the few dozen British volunteers with the quasi-Trotskyist POUM militia at the expense of the International Brigaders.

Born into a large, working-class family in rural Hampshire – his father was a carpenter – Bill Alexander joined the Communist Party in 1932, influenced by his mother’s politics and the sight of hunger marchers. His parents encouraged education and he gained entry to Reading University, where he studied chemistry. He then worked as an industrial chemist, but devoted much of his energies to his political and trade union activities, taking part, for example in the October 1936 Battle of Cable Street, which saw the police prevented from clearing a way for Sir Oswald Mosley’s fascist Blackshirts to march through the East End of London.

He joined the International Brigades in the spring of 1937 and was assigned to the 15th Brigade’s Anti-Tank Battery, an elite unit equipped with high-calibre Soviet guns. He became the battery’s political commissar, and was described by a comrade as ‘a strict disciplinarian, but fearless’. Cited for bravery at the Battle at Belchite in September 1937, he was promoted to commander of the British Battalion at the Battle of Teruel, during which he was wounded in the chest and shoulder and eventually repatriated in June 1938.

On his return to Britain he became Merseyside area secretary of the Communist Party until 1940, when he was accepted for a commissioning course at Sandhurst. He finished top of his year and served in North Africa, Italy and Germany, rising to the rank of captain in the Reconnaissance Corps. Resuming full-time party work after the war, he was the Coventry secretary until 1947 (and stood unsuccessfully as a Communist in Coventry East in the 1945 general election). He then spent six years as secretary of the Midlands area, and another six years as secretary for Wales, became assistant general secretary of the party in 1959, a position he held until 1967. He later taught chemistry in south-east London until retirement.