Alpha Centauri (The Curse of Peladon)

Alpha Centauri was an Alpha Centauran diplomat who had numerous dealings with the planet Peladon during its membership of the Galactic Federation. In their roles on Peladon, they had multiple encounters with the Doctor and regarded the Time Lord as a friend.

Biography
In 1881, Alpha Centauri, answering to a distress call which the Twelfth Doctor had sent, was willing to help Empress Iraxxa off her desolated home planet Mars, and welcomed both her and her Ice Warriors to the universe. At Alpha Centauri's request, the Doctor and Bill Potts created a message reading "God Save The Queen" to help guide the fleet Alpha Centauri dispatched. (TV: Empress of Mars)

Alpha Centauri attended Bernice Summerfield and Jason Kane's wedding in Cheldon Bonniface on 24 April 2010. (PROSE: Happy Endings)

Alpha Centauri first came to Peladon on the Committee of Assessment to review their petition to enter the Galactic Federation. They aided the Third Doctor in defeating the plans of Hepesh and Arcturus to sabotage the assessment. (TV: The Curse of Peladon)

Five years after Peladon joined the Federation, when Princess Lixgaar of New Mars was taken to Peladon for safety, Centauri locked the Princess away in the tower containing the chamber of the Prisoner of Peladon. They didn't wish to keep this a secret from King Peladon, but was insisted upon by the Federation council to "conceal the truth".

While hiding in the chamber with the Princess, the Third Doctor, who was with King Peladon, Lord Axlaar and Axlaar's accomplice, Sslurn, knocked at the double doors. Centauri opened the doors. The Doctor called for Princess Lixgaar within the chamber, whom Axlaar threatened with his sonic disruptor. The Doctor attacked Axlaar in the chest; the blast of the disruptor hitting Sslurn. Axlaar took aim again at the princess, swatting the Doctor aside, and King Peladon threw himself at him in a blind rage. After this, Axlaar fell from the window.

The next day, Centauri contacted Io. Izlyr arranged a Federation peacekeeping force to take the princess to safety. Centauri apologised for their betrayal to Peladon and announced their immediate resignation. Peladon suggested to Centauri that the refugees would need someone to grant them safe passage home and should relations between Peladon and the Federation continue, "we will need a full ambassador". Meanwhile, the Doctor quietly left in the TARDIS. (AUDIO: The Prisoner of Peladon)

Centauri contacted Lord Ixmari as he prepared to land on Peladon for an inspection, assuring him it was a fascinating planet. (AUDIO: The Ordeal of Peladon)

As ambassador to Peladon during Queen Thalira's reign, Centauri was tricked by Eckersley into summoning Federation troops when a mining dispute threatened the Federation's supply of trisilicate, providing a pretex for a group of renegade Ice Warriors led by the Ice Lord Azaxyr to declare martial law to take the trisiciliate for the Federation's enemies, Galaxy 5. Centauri subsequently helped the Third Doctor and Sarah Jane Smith expose the scheme and stop Eckersley and Azaxyr. (TV: The Monster of Peladon)

Later in Thalira's reign, Centauri was part of a group of delegates sent to Peladon following a galactic alert about plague and an imminent republican uprising, which the Queen believed was faked. They became friends with River Song, who had infiltrated the court as High Priestess Cantinca, and did not believe she was responsible after being poisoned from water River had given her. Releasing River from the cells after she told them her true identity, Centauri helped her expose the actions of Chancellor Gobran and the Arcturan delegate Ribble in contamianting the water supply with drugs and enslaving Subsumers. When River confronted the Karg Mafia agent posing as the Earth delegate, Centauri saved her by unleashing the Subsumers on him. Centauri subsequently planned to make a favourable report about the state of Peladon to the Federation. (AUDIO: The Poison of Peladon)

Centauri was present during the Seventh Doctor's efforts to recover the Diadem from Nic Reece on Peladon in 3984. They attempted to repeal the Doctor's execution alongside his companion, Bernice, with little success. (PROSE: Legacy)

They were still serving as the Federation ambassador to Peladon into the 41st century, when they were nearing retirement age. At this time, they escorted Princess Pandora of Earth to be wed to King Pelleas, unaware that she was being led to her death at the hands of Sekhmet. They non-violently stopped Arktos from taking trisilicate from a sabotaged mining operation and helped the Fifth Doctor and Peri return to the TARDIS in orbit around Peladon as a small detour.

Following the death of Pandora, as well as the Martian royalty, Prince Zixlyr and Princess Alixlyr, Alpha Centauri knew they had months of negotiation with the Earth and Martian governments to consider before retiring. (AUDIO: The Bride of Peladon)

Though semi-retired, Alpha Centauri continued to serve as a liasion between Peladon and the Federation during Queen Minaris's reign as relations became more tense. After a mining collapse they offered to organise Federation aid and was delighted when a survivor, Melanie Bush, revealed the Doctor had returned to Peladon. Centauri accompanied the Queen on a disastrous visit to the disaster zone, meeting the Sixth Doctor. Back in the Citadel, Centauri and Mel attempted to convince the Queen to act to help her people, but the Princess Isabelda accused them of attempting to influence a sovereign and had them confined to ambassador quarters. With Mel's encouragement, Centauri escaped with her and they discovered Isabelda's alien communications equipment inside the Temple of Aggedor, finding she had been talking to Arcturan. Arriving in the throne room as the Sixth Doctor was defusing an attack on the palace, Centauri and Mel helped exposed the Princess' plot, prompting the Princess to pull a gun with which she injured Centauri. Centauri recovered and organised Federation aid, deciding to remain on Peladon as a special ambassador. (AUDIO: The Death of Peladon)

Characteristics
Alpha Centauri had a squeaky falsetto voice, and was a genderless "hermaphrodite hexapod" according to the Doctor. (TV: The Curse of Peladon)

Though others sometimes employed the incorrect personal pronouns, Alpha Centauri actually used singular "they" pronouns. (AUDIO: The Poison of Peladon) Nevertheless, the Third Doctor sometimes referred to them with "he" and "him" instead, and had a penchant for addressing them as "my dear fellow". (TV: The Monster of Peladon)

Like most of their race, Alpha Centauri was a natural pacifist and a hypochondriac. Despite this, they demonstrated and developed a degree of courage during their time on Peladon, including their success in capturing the known criminal Arktos when he tried to steal Peladon's mineral wealth during Sekhmet's escape. (TV: The Curse of Peladon, The Monster of Peladon, AUDIO: The Bride of Peladon)

Behind the scenes

 * Alpha Centauri is referred to by masculine pronouns in The Curse of Peladon (excluding one instance when the Doctor says that they are an "it" rather than a "he" or "she") and The Monster of Peladon, as well as in their novelisations. This is also the case in Legacy, in which Geban is aware that they are really an "it". In The Poison of Peladon, The Death of Peladon and The Truth of Peladon, however, they are referred to almost exclusively with singular "they", with River Song angrily correcting others on pronoun usage.
 * Due to their appearance in Empress of Mars, Alpha Centauri held the title of the second longest interval between on-screen appearances, at 43 years. The number one spot is held by the Great Intelligence with 44 years. However, since the Great Intelligence switched voice actors in the intervening time, Ysanne Churchman held the honour for longest time taken to reprise a Doctor Who role, although the character, voiced by an impersonator, appeared in expanded media in the meantime. Indeed, taking expanded media into account both Alpha Centauri and the Great Intelligence are outdone by the thirty-nine years of Axos.
 * However, this honour was taken by Ian Chesterton as portrayed by William Russell, who had an incredible 57-year gap between The Chase and The Power of the Doctor, not only the longest time to reprise a role in Doctor Who history, but the longest in TV hostory as well.
 * Ysanne Churchman, who voiced Alpha Centauri in The Curse of Peladon and The Monster of Peladon, reprised her role for Empress of Mars. To keep the return of Alpha Centauri a surprise, Churchman was not credited in Radio Times.