A "bungled" Brexit and two years of "Tory Brexit chaos" have been hugely detrimental to the economy of the entire island of Ireland and threaten hundreds of thousands of jobs across Ireland and the UK, according to the head of Britain's biggest trade union.

Addressing the Unite trade union conference in Dublin, General Secretary Len McCluskey cited estimates that investment in Northern Ireland has already fallen by 54%.

He asked what business would want to invest when they cannot be confident of the trading or customs arrangements in six months time.

He said Unite, which has 1.4 million members across Britain, Northern Ireland and the Republic, could not downplay its concerns for jobs and skills in the Irish agri-food sector in particular.

However, he also warned that the consequences for the Good Friday Agreement of hardening borders must not be underestimated - as that would risk the delicate constitutional balance at the heart of the peace process.

Mr McCluskey, a supporter of Jeremy Corbyn and the British Labour Party, noted that Unite had campaigned for Remain, pointing out during the campaign the impact of leaving the EU including jobs, a race to the bottom on workers' rights, as well as consumer and environmental issues.

However, he said the "inconvenient truth" was that Remain had lost the argument, and they had to recognise the democratic legitimacy of the Brexit vote - even though Northern Ireland had voted to remain.

He reiterated his union's position that only the Labour Party under Jeremy Corbyn could find a solution which could bring the UK together, and stated: "I say to those demanding a second referendum that yes, I want a people's vote, but a real people's vote. It's called a general election."

He said the challenge now was to make Brexit work, and secure a Brexit "on our terms".

Mr McCluskey told delegates that while the price of a Tory Brexit and their pursuit of free trade deals included opening the door to cheap steel and tyre imports and US companies buying up NHS trusts - leaving working-class people in Britain to pick up the tab - the price for working class communities in Northern Ireland includes political instability and a possible return to violence.

Mr McCluskey described the failure of parties in Northern Ireland to negotiate a return to power-sharing was inexcusable, as it was creating a vacuum into which the politics of sectarianism and hate walked easily.

Despite Unite's close links to the UK Labour Party, Mr McCluskey said he "despaired" about what had happened to the Irish Labour Party, describing it as having "utterly lost its way" on who and what it was.

He described their decision to support a Fine Gael government as "disastrous", saying he did not know what they were thinking, and that they had subsequently been punished by the electorate.

He called for a new alternative radical political platform to create an authentic voice for working people.