Passameer - Day Branch The Passameer - Day Slitheen were a branch of the Raxacoricofallapatorian criminal family Slitheen . History . 21st century . The Passameer - Day Slitheen , like the rest of their family , were originally from Raxacoricofallapatorius . After the Slitheen bribed their way into government , their rule crashed the planet ' s economy and the population rose up against them . ( TV : " The Gift " ) Exposed , shamed and arrested " en masse " in the , the entire family was tried and found guilty in perpetuity and given the death sentence with no chance of appeal . Many of the Slitheen fled justice , but the family continued to be hunted down by the Blathereen and Judoon . ( TV : " Revenge of the Slitheen " ) In March 2006 the Passameer - Day Slitheen disguised themselves as various human s holding leadership positions and seized control of the UK government in an effort to start a nuclear war . They crashed their spacecraft into the Thames , faking an alien invasion to make the UN give them the codes to nuclear weapons . They also had a bigger ship in orbit above the North Sea . Their goal was to turn the Earth into a huge nuclear reactor pile and sell its remains off as starship fuel . This attempt was foiled by the Ninth Doctor and his allies . All of them , apart from Blon Fel - Fotch Passameer - Day Slitheen were killed when 10 Downing Street was destroyed by a missile fired by Mickey Smith . In Blon ' s case , she managed to escape at the last moment using an emergency teleport that took her to the Isle of Dogs . ( TV : " Aliens of London " / " World War Three " , " Boom Town " ) In September of the same year , Blon , the last surviving member , got herself elected Mayor of Cardiff and tried to use her office to blow up Earth by destroying a local nuclear reactor . The Cardiff Space - Time Rift would amplify the explosion so it would not only destroy Earth but enable her to escape the planet . This effort was also foiled by the Doctor and his allies . Blon was then regressed back into an egg by the heart of TARDIS so she could have a second chance at life . The Doctor returned the egg to Raxacoricofallapatorius and gave it to a family who adopted her . ( TV : " Boom Town " ) Despite this , the Passameer - Day Slitheen survived . In the year 5000000000 , a Slitheen child , Klov Dreb Fotch Passameer Day Slitheen III stowed away on the Doctor ' s TARDIS for an adventure . He stole cheese sandwich es , chip s and chocolate biscuits in the TARDIS for three weeks . The Moxx of Balhoon alerted the Tenth Doctor and Martha Jones that the Slitheen had accused the Doctor of abducting their child . He tracked Klov to the TARDIS , under a floor panel in the console room . The Doctor took him back to his home , but first stopped by the planet Morbel , an ocean planet with the biggest log flume in the galaxy . ( WC : " Who Ate All the Biscuits ? " ) " As the Slitheen made a criminal accusation against the Doctor , it is likely that by the year 500000000 the Slitheen are no longer a criminal family . " Legacy . The attempt of the Passameer - Day Slitheen to reduce the Earth to molten slag and sell it would prove an important moment in the history of the Slitheen family . It was a crushing failure to become rich . Several attempts were made to profit on Earth again , but none succeeded . ( TV : " Revenge of the Slitheen " , " The Lost Boy " , " From Raxacoricofallapatorius with Love " , " The Gift " ) . These failures played a vital role in the downfall of the Slitheen and placed them in the shadow of their successful cousins and enemies , the Blathereen family . ( PROSE : " The Monsters Inside " )