Creatives must "get their act together and speak with a united voice" to protect the future of the sector post-Brexit, according to London Design Festival and Creative Industries Federation founder John Sorrell.

Sorrell said that architects, designers and other creatives needed to be "intensely practical" and clear on the issues that need to be fought for as the UK government decides on its priorities around Brexit.

"If ever there was a time for us to all to get our act together and speak with a united voice, it is now," Sorrell told Dezeen.

He said it was crucial that the sector presented a clear message to the government about both its impact on the economy and what it needs to continue to thrive.

"Freedom of movement of talent, access to markets and funding and IP protection have all been fundamental to the growth and success of our sector – and were part of what we have enjoyed as EU members," he said.

"In the wake of the referendum result, some of these benefits could be lost so it is crucial that we are intensely practical about identifying what we need the government to be fighting for in the Brexit negotiations on our behalf."

His comments echoed those of designers and architects who attended Dezeen's Brexit design summit in June, who said that the sector had traditionally struggled to present a unified voice to government.

"The creative industries don't really have one single voice, and this is what we need more than anything," said industrial designer Paul Priestman.

Sorrell is the founder of the London Design Festival and the Creative Industries Federation – an independent membership body that lobbies government on behalf of creative businesses, institutions, charities, organisations and individuals.

Its members voted overwhelmingly to remain in the European Union. It is now working to ensure the sector is considered in Brexit negotiations and the government's industrial strategy, and is organising a series of meetings with members and creative professionals around the country.

Dezeen spoke to the CIF as part of an ongoing project to create a manifesto outlining the key issues that must be addressed to help the sector thrive after Brexit.

"Dezeen's initiative mirrors and reinforces what the Federation is doing across a wider cross section of the creative industries and we can all work together to reinforce the message to government," said Sorrell.

"The more people are actively involved in this the better. But we need a clear message."

A number of designers and architects – including Amanda Levete, Tom Dixon and Ilse Crawford – have already contributed ideas for the manifesto, with common themes including access to talent, support for education and exchange programmes, and the adoption of EU intellectual property laws.

According to government statistics, the creative industries generate almost £10 million an hour in the UK, and are worth more than £84.1 billion a year to the economy.

In 2014, the last year covered by the government's data, the sector grew by 8.9 per cent – almost double the rate of the economy overall.

A recent report published by innovation charity Nesta found that employment within the creative industries was also growing faster than overall employment rates.

But a number of architects have already reported job losses connected to delayed projects and client uncertainty after the referendum.