More than 130 MPs and peers including Michael Grade, Joan Bakewell, Floella Benjamin and David Puttnam have backed a call for a specific package of support for the UK’s creative industries.

They have signed a letter to the government warning that support announced as part of the coronavirus crisis has so far failed to reach “the very large numbers of directors of small limited companies, freelancers or agency workers that keep our creative industries booming”.

The letter predicts that unless action is taken quickly, creative industry workers and their families will be “left with no option than to join the ever-growing queue for universal credit”.

Daisy Cooper, the Lib Dem spokesperson for digital, culture, media and sport (DCMS), who co-ordinated the letter, pointed to the example of Germany, where the federal government quickly announced an aid package for its creative and cultural sectors.

She said thousands of families were facing financial hardship. “While we saw government step in to stabilise banks in 2008, we have not seen the same urgency for the plight of many across the creative industries who are self-employed, freelancers or agency workers.

“Unlike Germany, the government’s response has been too slow. Ministers must resolve the gaps in their plans and come forward with adequate support or risk decimating Britain’s world leading creative industries, one of the fastest growing parts of the UK economy.”

The vast majority of people who work in the creative industries are far from being rich or famous. They are, the letter says, in a wide range of jobs which includes designers, set builders, scriptwriters, actors, singers, dancers and video directors.

The letter has been signed by more than 60 MPs from all the main political parties as well as peers, many of whom had and have careers in the creative industries. They include Grade, Bakewell, Benjamin, Puttnam, Rosie Boycott, Beeban Kidron, Melvyn Bragg and Michael Cashman.

Written to the culture secretary, Oliver Dowden, and chancellor, Rishi Sunak, the letter calls on the government to hold a virtual forum with groups and businesses in the creative industries “and agree measures the government can take to support this vitally important sector and a clear timeline for its urgent implementation”.

It is also backed by trade bodies. Tom Kiehl, the acting chief executive of UK Music, said many people in the industry were required to be company directors because of the nature of their work but were disqualified from help for the self-employed and could not furlough without damaging their work.

“We are urgently seeking government help to make sure these individuals, often low earners, do not slip through the net.”

Caroline Norbury, the chief executive of the Creative Industries Federation, said the sector was being hit hard by the coronavirus. “With theatres, venues, museums and galleries closing, film shoots being postponed and festivals being cancelled, many creative professionals are facing an uncertain future.”

The creative industries, Norbury said, would be critical to driving the UK’s recovery as well as transforming lives for the better in all communities.

“For our sanity, our culture and our sense of shared experience, it is imperative that creative professionals are protected and supported through this crisis.”

The cross-party digital, culture, media and sport committee is also carrying out its own inquiry into the impact of coronavirus on the sectors it covers, including the creative industries. It expects to hold evidence sessions from late April in to May.