The Brexiteer criticised Rachel Johnson and said Brexit was looking much rosier than she wished.
Speaking on The Pledge on Sky News, the pair clashed after Ferrari labelled the europhile a “Remoaner”.
He referred to a survey of entrepreneurs by the Institute of Directors, which said 83 per cent of young firms were optimistic about their prospects in the year ahead.
He said: “Don’t characterise it all to the UK side. I think the EU have been incredibly obstructive and let’s just pause and think.
“Quite an important piece of research came in today, an Institute of Directors report that says there is tremendous confidence about British business.
“It’s been a bad week but it’s not as bleak as you Remoaners would paint it, truly.”
Johnson, the Foreign Secretary’s sister, took offence at the term and poked fun at the Brexiteer saying he was “coming round’ to europhile arguments.
She said: “Please don’t call me a Remoaner, come on, let’s try and keep this nice.
“Actually you’re coming round to our side of the argument.”
But Ferrari was not having any of it.
He said: “We have to Brexit, it’s a fact.”
A leaked paper from Brussels has claimed the UK will be forced to accept edicts from Brussels after Brexit despite not being allowed to have a say on legislation.
Despite the UK voting to wrestle back control from the bloc, the European Parliament draft proposal will allow the EU to tell Britain what to do during any post-Brexit transition period.
Theresa May set out a transition period of two years following Brexit in her Florence speech – in which she laid out her red lines for Brexit.
Chancellor Philip Hammond had previously pushed for a lengthy transition of up to three years – while hardline Brexiteers including Tory MP Owen Paterson described putting off the nation’s EU evacuation as ‘absolute tosh’.
The European draft paper outlines a slew of concessions, including limiting UK benefits from future EU agreements and forcing British courts to abide by the European human rights convention.