Three quarters of creative industry jobs in the past 18 months went to people who had a friend or contact in the sector, research from Bectu’s Big Survey found.
The findings showed 75% of workers got jobs through friends or contacts, rising to 82% in film, TV drama and fashion.
In theatre, the figure was 64%.
Just 37% of jobs were advertised publicly, dropping to 25% in TV drama, 27% in film and 27% in fashion.
Only 37% of all workers said they had a formal interview.
This dropped to 23% for fashion, 30% for film and 31% for TV drama.
The survey also found 22% of workers hid information about a life commitment, situation or diagnosis when applying for roles.
This was 45% among disabled workers and 37% for carers.
More than half (55%) of workers had a job cancelled at short notice in the past year. 43% said they started work without a formal booking confirmation.
Philippa Childs, head of Bectu, said: “These findings make clear that the creative industries continue to operate a closed hiring culture which is leaving many talented workers out in the cold, often driven by last-minute decision-making by studios that incentives people to hire those they already know.
“This is a vital sector of the economy, but these archaic hiring practices mean that many talented professionals find it impossible to build a career in the sector because they lack the right connections, wasting their talent and crushing their hopes of a creative career.
“The situation is much worse for those from marginalised backgrounds.”
Childs added: “Creative talent isn’t the preserve of white middle class people with social capital, but if nothing changes then we will find that these are the only people able to get ahead in the sector.”