"If employment status is going to change, we may no longer have the distinction between worker and self-employed".
Before announcing the scheme, the Chancellor described it as the "next step in the economic fight against the Coronavirus pandemic".
Mr Sunak had previously promised to cover 80 per cent of the salaries of Brits who are in employment but, as it stands, the self-employed can only claim Universal Credit - which he raised to £94.25 a week - if they need to abandon work.
"It seems grossly unfair that employees of all incomes are covered up to £2,500 per month by the JRS, yet high-earning contractors are penalised during a time of national crisis because they are good at what they do". Grants will be paid in a single lump sum instalment covering all 3 months, and will start to be paid at the beginning of June.
The scheme will be open to those with a trading profit of less than £50,000 in 2018-19 or an average trading profit of less than £50,000 from 2016-17, 2017-18 and 2018-19.
The Chancellor noted that the SEISS would be available for at least three months and extended if necessary, and that self-employed would be able to claim and continue to do business.
"95 percent of people who are majority self-employed will benefit from this scheme".
Mr Sunak said: "To support those who work for themselves, today I am announcing a new self-employed income support scheme".
To minimise fraud, only those who are already in self-employment and meet the above conditions will be eligible to apply.
The Chancellor said "it provides an unprecedented level of support for self-employed people".
According to reports from government sources, setting up this system is much more complicated for self-employed people given that their incomes are often irregular and some are not on PAYE schemes.
'For many people that have seen their businesses disappear in the blink of an eye, things like statutory sick pay or universal credit just isn't enough, ' Dr Adam Marshall, director general of the British Chambers of Commerce told the BBC's Today Programme this morning.
The Chancellor's coronavirus press conference.
"Many freelancers and self-employed people will already be seeing their finances stretched to breaking point".