Other programmes Vulliamy worked on included an investigation into neo-Nazi movements in Europe and Britain arming loyalist militias in the North of Ireland; a documentary about assisted dying for the terminally ill; a film about the last olive groves to be demolished and first stone laid for the Israeli West Bank settlement of Maale Adumim; an investigation into Indigenous Aboriginal Australians dying from mining asbestos in New South Wales; and a special report on Ronald Reagan's 'Star Wars' space-based missile project, which included an interview with the inventor of the atomic bomb, Edward Teller.

[1] He testified for the prosecution in ten trials at the ICTY, including those of Bosnian Serb leaders Dr. Radovan Karadžić and General Ratko Mladić.

In 1991, Vulliamy also covered the aftermath of the Iraqi invasion of Kuwait, in Iraq, revealing atrocities by Saddam Hussein's troops in the Shiite South.

Later, he reported on the lynching of James Byrd in Jasper, Texas, and on its slipstream, penetrated the white supremacist backstory behind the killer's world, in jail and among fringe religious compounds.

He clashed with his newspaper, The Observer, over its support for the invasion, often unable to place his stories about false intelligence and non-existence of weapons of mass destruction in the paper (see Official Secrets film below, 2019).

[1] This work led to his book Amexica: War Along the Borderline, which in 2013 won the coveted Ryszard Kapuściński Award – named in honor of the writer, creator and master of the genre.

Reviewing 'Amexica' in the New York Times, Tamara Jacoby wrote: "Vulliamy, with a mix of irony and pathos, writes like a latter-day Graham Greene — the detached foreign observer who has seen it all yet really cares".

In 2013, Vulliamy wrote liner notes for a CD box set of solo records by Robert Plant of Led Zeppelin and in 2017, contributed an essay to the book which accompanied the 50th anniversary edition, remixed by George Martin's son Giles, of The Beatles 'Sgt.

In September 2022, the RTÉ Concert Orchestra - conducted by Ciarán Crilly with soloists and choir - premiered a Cantata about the Irish Civil War, 'Who'd Ever Think It Would Come To This?

In 2019, Vulliamy was by played the actor Rhys Ifans in Gavin Hood's acclaimed Hollywood film Official Secrets about the case of Katharine Gun, a GCHQ agent who blew the whistle on illegal bugging of UN diplomats during the lead-up to the Iraq invasion of 2003, with Keira Knightley in the lead role.

Vulliamy features in the film furious at censorship by his own paper of a story he filed during October–December 2002 from an inside CIA source, Mel Goodman, affirming that Iraq had no weapons of mass destruction, while intelligence was being 'cooked' by a special office in the Pentagon – and then locating the NSA secret agent, Frank Koza, who ordered the illegal bugging.