ES News email The latest headlines in your inbox twice a day Monday - Friday plus breaking news updates Enter your email address Continue Please enter an email address Email address is invalid Fill out this field Email address is invalid You already have an account. Please log in Register with your social account or click here to log in I would like to receive lunchtime headlines Monday - Friday plus breaking news alerts, by email Update newsletter preferences

Jeremy Corbyn was today under growing pressure to “come off the fence” on Brexit and abandon his strategy of “deliberate ambiguity” about leaving the European Union.

Writing in tonight’s Evening Standard, former Labour shadow chancellor Chris Leslie said: “A sheepish silence in the hope that Brexit will just pass us by will not work any longer.”

Calling on Labour’s leader to whip the 262 Labour MPs behind a job-saving vote to keep Britain in the EU customs union, he said it would be “unforgivable” to do nothing in the face of evidence that the poor would be hit hardest from leaving the frictionless trading bloc.

“Taking a path of deliberate ambiguity in the hope we won’t offend anyone is not the principled stance that the vast majority of Labour’s membership expect from this leadership team,” writes Mr Leslie.

“This is the defining issue of our times and it is not going to go away. We have a responsibility to prevent the austerity that will hit the poorest hardest.”

Other senior Labour figures also warned that Labour’s new mass membership of idealistic young activists would become disillusioned if Mr Corbyn failed to act in case he offended Leave voters in the party’s old heartlands.

Former shadow communities secretary Emma Reynolds urged Mr Corbyn to let the membership vote on a Brexit strategy. “Jeremy Corbyn has always been keen on involving party members in policy-making so I don’t see why not, and we should discuss it at our next party conference because we didn’t discuss it last year. “

Will Dry, of pressure group Our Future, Our Choice said Labour’s stance was “morally dubious and politically empty”. He said most young Labour activists assumed Mr Corbyn was opposed to Brexit and would be disenchanted if he did not fight it.

Meanwhile, Australia officials today warned that a customs union with the EU would hamper a future trade deal with the UK.

High Commissioner Alexander Downer said the two countries could do “substantially” more trade but only if Britain was free from EU rules.

“If you remain in the customs union then you would have no control over an independent trade policy,” he told the BBC’s Today.

A poll last week revealed Labour’s vote share would tumble from around 42 per cent to just 30 per cent if the party was seen to side with Conservatives in going ahead with Brexit - allowing the Tories to win a general election with a 12-point lead.

It comes as plans for a Commons vote instructing Mrs May to try to stay in the EU customs union were announced by former shadow business minister Chuka Umunna and Tory former Business Minister Anna Soubry.

In a bid to regain the initiative on Brexit after weeks of public Cabinet tensions, the Prime Minister is preparing two keynote addresses this month.

Speeches will also be made by three Brexiteers - Foreign Secretary Boris Johnson, Brexit Secretary David Davis, and International Trade Secretary Liam Fox - plus Remain-backer David Lidington, the Cabinet Office Minister.

Mrs May’s first address on post-Brexit UK-EU security will be made in Germany next Saturday.

Another speech in three weeks will set out her negotiating stance, following a special “away day” summit of the “Brexit war Cabinet” at Chequers.

Mrs May met Irish premier Leo Varadkar today for talks on ending the 13-month political stalemate in Northern Ireland. They were also likely to discuss how to avoid a hard border in Northern Ireland.

Britain should unilaterally abolish tariffs to give it an edge in Brexit talks and drive down prices for consumers, a new report from the Policy Exchange think tank said.