Shadow chancellor to outline Labour party’s plan to incentivise companies to invest their money and for UK to be capital of technology in Europe

John McDonnell, the shadow chancellor, will promise “socialism with an iPad” as he promises Labour will make the UK one of the world’s great technology centres but also provide security for the army of new workers, many self-employed, who have been casualised by the internet.

He will also set an objective that 3.5% of UK gross domestic product is spent on infrastructure, part of a move to what he describes a new strategic state.

McDonnell’s pledge came as Lord Livermore, the party’s election coordinator in the May general election, said Labour was travelling further from electoral success under Jeremy Corbyn, and one of the far-left groups, Left Unity, prepared to vote on whether to dissolve itself and join Labour or to seek to affiliate as an independent party.

Left Unity was set up with the help of film director Ken Loach in 2013 and is one of many far-left groups deciding how to respond to Corbyn’s victory. Left Unity has suffered 400 resignations as its former party members jointhe Labour party under Corbyn.

After another rocky week for Labour, McDonnell will try to steady the ship by setting out a vision for a Labour economy in which the UK diversifies, and becomes the technological as well as the financial centre of Europe.

In an article for the Guardian, McDonnell says the internet has opened up new possibilities such as Airbnb, a service through which others can rent out space in their home, but he warns that this so-called “gig economy” may restrict rather than expand opportunities for workers.

How Labour will secure the high-wage, hi-tech economy of the future | John McDonnell Read more

In a speech on Friday at Imperial College, London , McDonnell will promise to “re-establish the supply chain between shop floor and government that has broken down in recent years, bringing workers and unions together to advise policy-makers on the future direction of the economy.”

He will also promise to establish “an Innovation Policy Council with a clear, mission-led goal to boost research and development spending and maximise the social and economic benefits from that expenditure”.

He will suggest that infrastructure spending can be boosted by changing the corporate tax system so companies have incentives to invest the £400bn cash pile on which they are sitting.

One option to achieve this would be a higher tax on retained earnings.

The gig economy, he will warn, “may be a nice phrase, but can hide a grim reality for those who depend on the new world of work for their livelihood”. He will argue that “millions of workers are excluded from the hard-won protections of formal employment contracts. And relentless pressure is placed on those, the majority, still protected”.

The McDonnell speech comes after the head of Labour’s 2015 election campaign called on Corbyn to publish an internal inquiry into its election defeat, warning that his leadership has taken the party even further from possible victory in the next election.

Spencer Livermore, who ran Labour’s unsuccessful election bid earlier this year, said: “It is important we have as wide a debate as possible about why we lost to make sure we learn the right lessons, and publishing that report is an important contribution to that debate.”

The formal report into the party’s election defeat, chaired by Margaret Beckett, was commissioned by the interim leader, Harriet Harman. Beckett, a former deputy Labour leader, is understood to have sent the completed report to Corbyn’s office in the past week, and is awaiting a response.

Speaking to BBC Radio 4’s World at One programme, the report is said to have asked: “What progress [has the Labour party] made so far against the enduring weaknesses that led us to lose in 2015? Are we further ahead now on economic credibility?

“Do the British people see our leader as a potential prime minister and have we broadened the base of our project in the country ? If you look at all those things it is impossible to conclude anything but [that] we are further away from power than we were on 8 May. Elections are won or lost in the first months of a parliament.”

Livermore accepted Corbyn has a strong internal mandate but said: “As a leader he has a responsibility to translate that into external support and right now he has the lowest rating of any leader of the opposition in history.

“I believe Mr Corbyn has failed to learn the lessons of why we lost in 2015 and unless he does on the present course we will lose in 2020. On the fundamental issues we are going backwards not forwards”.