Tony Benn’s son has joined the House of Lords in an uncontested byelection, six decades after his socialist stalwart father renounced a hereditary title. Dr Stephen Benn, 69, also known as Viscount Stansgate, will join Labour’s group on the red benches in parliament’s upper chamber. The appointment represents a marked departure from the stance taken by his late father, who campaigned to be able to shed his aristocratic position and called the hereditary peerage system “absolutely mad”. Tony Benn was the Labour MP for Bristol South East before inheriting the title Viscount Stansgate on his father’s death in 1960, triggering his automatic expulsion from the Commons owing to rules prohibiting people from being a member in both places. The leftwing firebrand fought successfully to overturn centuries-old rules, enabling him to renounce his title in 1963 and return to the elected Commons, where he served until stepping down prior to the 2001 election “to spend more time on politics”. He gave a famous analogy in 2011 to decry the power handed to unelected individuals to make and scrutinise laws by bloodline, saying: “I wouldn’t like to go to a dentist who, just before he drilled my teeth, told me he was not a dentist himself but that his father had been a very good dentist.” When Benn died in 2014, his eldest son was able to claim the title owing to the way hereditary peerages are handed down. The number of peers who have them was reduced significantly under reforms made by Tony Blair’s government. However there are still 92, and when such a member dies or retires, peers in their parliamentary group choose a replacement through a byelection. Viscount Stansgate was the only candidate for the vacancy caused by the death of Lord Rea last year, and so no ballot was held and he was appointed automatically. Benn, who is the director of parliamentary affairs at the Royal Society of Biology and has been a Labour member for more than 40 years, said in his candidate statement that he would be a “working peer” and would focus on “developing the relationship between science and parliament”. In taking up his seat, he will be able to help shape the nation’s laws and claim tax-free allowances of up to £323 a day for attending sittings. There have been repeated demands in the Lords to scrap the contests used to fill vacancies caused by the death, resignation or expulsion of hereditary peers. The system has faced widespread criticism given the exclusive male-dominated list of eligible candidates and the limited number of people able to vote. A Conservative peer welcomed Benn’s elevation, saying: “If he serves the Lords as well as his father served his constituents then he will be a very respected member.”