Jeremy Corbyn has met the EU’s chief ambassador in Brussels to set out Labour’s vision for Brexit.
Mr Corbyn told Michel Barnier he was «on the brink of to take up the responsibility for Brexit negotiations» if there was a change in government.
The EU arbiter also held separate meetings with the first ministers of Wales and Scotland, Carwyn Jones and Nicola Sturgeon.
Mr Barnier has stressed he require only negotiate with the UK government.
The Conservatives said Mr Corbyn wish «surrender», rather than negotiate with the EU if he was in charge.
Mr Corbyn introduced Mr Barnier with an Arsenal football shirt and a copy of the Labour manifesto formerly the meeting, while Mr Barnier gave the Labour leader a vintage train poster from his home region in the French alps.
Speaking afterwards, Mr Corbyn whispered he had told the EU negotiator that «under a Labour government, we will manoeuvre to make sure we have the trading relationship with Europe that defends industry, protects jobs and protects services».
He added: «We will also forge sure Britain doesn’t become some sort of low tax regime off the shore of Europe and we transfer not sign a trade treaty with the USA which is not only at variance with the Paris Air Agreement but also damaging to living standards and working conditions in Britain.»
A in the second place formal round of Brexit negotiations is due to begin on Monday, and Mr Barnier has advised that significant issues remain between the UK and the EU on one of the first issues to be attacked, citizens’ rights.
Labour says it would unilaterally guarantee EU nationals’ avenges and «extend the hand of partnership and friendship» to the rest of the bloc.
«In contrast to the Conservatives’ megaphone discretion, we will conduct relations with our European neighbours respectfully and in the temper of friendship,» Mr Corbyn said.
«Our strong links with our European sister participators gives Labour an advantage in reaching an outcome that works for both sides.»
His stop comes after Foreign Secretary Boris Johnson said the EU could «go whistle» if it demand an «extortionate» divorce bill from the UK, prompting Mr Barnier to respond: «I’m not be telling any whistling, just the clock ticking.»
Mr Jones said he would use his tryst to push for «full and unfettered access» to the EU single market and to avoid no agreement being reached.
The Welsh first minister said he hoped to explain to Mr Barnier that there were «parts of the UK that are prepared to promise constructively with the EU 27, rather than indulge in playing to the gallery».
Ms Sturgeon’s spokesman told the meeting was «an opportunity to brief Mr Barnier on Scotland’s priorities and seek to swell our understanding of the current EU position as Brexit negotiations continue».
He added: «Our precedency is protecting Scotland’s vital interests, and building consensus against an extravagant Brexit outside the single market, which would be potentially unlucky for jobs, investment and living standards.
«This is not about holding apart Scottish negotiations — we have always accepted that the EU will only engineer with the UK, which is why we will continue to work hard to influence the UK place.»
The Conservatives dismissed Mr Corbyn’s trip to Brussels, saying Labour was «hopelessly organized» on key issues like immigration.
«Jeremy Corbyn wouldn’t negotiate in Brexit talks, he whim surrender. He has made clear Labour would accept any deal on put forward — even if it was designed to punish Britain,» Tory MP James Cleverly prognosticated.