No help for self-employed and freelance workers hit hard by coronavirus will be unveiled today, Rishi Sunak has suggested – warning it is “incredibly complicated to design”.

The chancellor is under growing pressure to act “urgently” – after Boris Johnson ordered all-but "key workers" to stay home – but pleaded with MPs to give him more time.

Mr Sunak promised “further announcements”, but warned: “There are genuine practical and principled reasons why it is incredibly complicated to design.”

He added that there were “genuine questions about practicality, fairness and delivery, which is why it requires careful thought”.

The delay was revealed as the Prospect union warned that “freelancers are crying out for help”, as their livelihoods disappear.

“They need it today so they can pay their bills at the end of the week. If they can’t, the whole economy suffers,” said Mike Clancy, its general secretary.

Bectu, the union for freelancers in the media and entertainment sectors, said the government’s existing offer would be worth just £4,800 a year to its members – when normal average earnings were £38,000.

Mel Stride, the Conservative chairman of the Commons Treasury committee, revealed it had been flooded with pleas for help, after launching an inquiry.

“We have received over 14,000 responses, mostly on issues relating to self-employment, from people who work in a wide variety of professions, including childminders, taxi drivers and hairdressers, he warned.

John McDonnell, Labour’s shadow chancellor, said people were being forced to choose “between health and hardship”, raising staff on zero hours contracts but not on PAYE schemes.

“We need some urgent action for this sizeable group of workers, at least nearly a million zero hour workers – maybe at least another million more.”

Mr Sunak revealed the Treasury was “actively considering the question of how best to average earnings of people in this situation”

But he raised the problems of using tax returns that would be a year and a half out of date and provoked some anger when he warned cash would also go to people “who are much more wealthy”.

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And he warned that, while “we would hope to have something to say very shortly, in terms of something being implemented, that will take longer”.

MPs on all sides urged Mr Sunak not to let the perfect be the enemy of the good, as the self-employed were forced to travel to work to get an income – while being ordered to stay home.

The chancellor said: “Rest assured that we absolutely understand the situation that many self-employed people face at the moment as a result of what’s happening and are determined to find a way to support them.