Nearly three quarters of the peers created since the general election are party political apparatchiks, including former MPs, special advisers and party aides, a new analysis reveals.

Since May’s general election, 62 new peers have entered the Lords, including four hereditary peers and two bishops. However, by far the largest group of new peers are retiring, former or deselected MPs and MEPs – 28 of the total, according to an analysis by the Scottish National party.

Four former government special advisers and a number of Conservative party officials have also been introduced to the Lords.

The party insiders include Catherine Fall, a former deputy chief of staff to the prime minister, Simone Finn, a special adviser to trade minister Francis Maude, and a former agriculture minister, Douglas Hogg. Hogg stepped down as an MP at the 2010 election, shortly after it was revealed that he had claimed £2,000 in parliamentary expenses to maintain a moat around his country estate, which he had listed as a second home.

Only four academics and two third-sector figures have become peers over the same period.

Kenneth Gibson, an SNP MSP, said the figures provided fresh evidence of the need for Lords reform. He also called on the Labour leader, Jeremy Corbyn, to fulfil his promise not to appoint any peers to the Lords until it has been reformed. Labour has appointed six peers since the election.

“Supporters of the unelected … Lords often argue that it allows expert, outside experience to scrutinise legislation – these figures put the lie to this myth and show that it is nothing more than a house of cronies,” said Gibson. “The facts speak for themselves – House of Lords appointments are overwhelmingly being used to reward loyal politicians and advisers or as a consolation prize for losing elections. And to have 26 bishops in the Lords is a nonsense. It is beyond belief that this is tolerated in a democratic country.”

According to the SNP, 35 Conservative peers have been created since May, along with eight Labour, six crossbenchers, 11 Lib Dems and two bishops.

The fresh calls for reform come in the wake of the revelation this month that the Speaker of the House of Lords has racked up large expenses for chauffeur-driven cars to wait for her while she was at the opera and at a lunch in central London. Lady D’Souza kept a chauffeur waiting for four hours at a cost of £230 while she watched a performance of Benjamin Britten’s Gloriana. The journey from parliament was just one mile.

She also spent £270 holding a car for four-and-a-half hours while she had lunch with the Japanese ambassador. D’Souza also used a Mercedes to get from Westminster to Canterbury for the enthronement of Justin Welby as archbishop at a cost of £627.

According to a freedom of information response, the lord speaker spent tens of thousands on business-class flights, staying in £300-a-night hotels.