Labour has drawn up secret plans to throw open Britain’s doors to thousands of unskilled migrants after Brexit.

An internal policy document leaked to the Daily Mail reveals the party is considering introducing a visa for migrants seeking ‘low-skilled, unskilled or seasonal work’.

The document, drawn up this month by Jeremy Corbyn’s domestic policy adviser, Lachlan Stuart, also proposes axing rules which limit foreign spouses living here unless they can show they will not be a ‘burden’ on the taxpayer.

The document, drawn up by Jeremy Corbyn’s domestic policy adviser, reveals the party is considering introducing a visa for migrants seeking ‘low-skilled, unskilled or seasonal work’

Labour’s manifesto made no mention of a plan to allow in more unskilled migrants. Mr Corbyn has repeatedly refused to say whether he thinks immigration levels are too high. It came on a day of chaos for Labour in which:

Mr Corbyn suffered another ‘car-crash’ interview on the BBC’s Woman’s Hour show in which he was unable to say how much his flagship childcare policy would cost;

The Labour leader was forced to apologise after his supporters bombarded presenter Emma Barnett with vile anti-Semitic abuse, on the day he was launching the party’s policy to tackle anti-Semitism;

Mr Corbyn was branded a ‘huge disappointment’ by users of the Mumsnet website after he cut short an election chat with mothers;

Labour’s shadow foreign secretary Emily Thornberry faced mockery after suggesting British farmers could not increase exports to Australia after Brexit because the food ‘would go off’.

Labour’s manifesto promises ‘fair rules and reasonable management’ of immigration, but gives few details on the type of regime it would operate after Brexit.

Mr Corbyn, who has always opposed a cap on migration, said on Monday that immigration would ‘probably’ come down under Labour, but added: ‘Don’t hold me to that.’

Emma Barnett, pictured with Jeremy Corbyn, was targeted by vile trolls after skewering the Labour leader over his childcare policies in a Woman's Hour interview

The BBC reporter, pictured on television, was compared to a pig and branded a Zionist online

The leaked policy document suggests Labour’s plans could add tens of thousands every year to net migration, and will cause alarm in working-class Labour constituencies which voted for Brexit.

The document says Labour would also relax rules on handling asylum claims if it wins power.

The party last night confirmed the document was genuine but insisted it was only one of several ‘discussion documents’ and was not yet official policy.

But the document appears to set out a detailed blueprint that Labour will pursue if Mr Corbyn wins power next week.

It reveals that Labour would open ‘tier 3’ of the immigration system to new applicants for the first time. This route into Britain, which was one of the five original tiers created by Labour in 2008, was never used because of the huge influx of migrants from Eastern Europe.

Tier 1 visas are for entrepreneurs and business investors, tier 2 for skilled migrants sponsored by UK businesses, tier 4 is student visas and tier 5 offers temporary visas for young people aged 18 to 30. All four are operating.

In March 2013, David Cameron announced tier 3 would be ‘shut down completely’ in a speech in which he questioned why it was even created.

‘There was even, extraordinarily, a tier specifically created for those with no skills at all. Now why would you want to create such a tier?’ he said.

Jeremy Corbyn, pictured at the race and faith manifesto launch in Watford, has repeatedly refused to say whether he thinks immigration levels are too high

But in Labour’s policy document, a senior official writes: ‘We envisage a requirement to make continued use of the current five-tiered tiered visa system, including the currently unused tier applicable to those seeking low-skilled, unskilled or seasonal work.’

The document also proposes scrapping the means test which limits some family migration.

Anyone wanting to bring in a spouse or partner from non-EU countries has to meet a before-tax income requirement of £18,600.

Introduced by Theresa May when she was Home Secretary, it was designed to stop wives or husbands becoming a ‘burden on the State’.

The Tories have pledged to increase the minimum amount, but scrapping it entirely could – according to official figures – add between 14,000 and 18,000 a year to migrant numbers.

The basis of Mr Corbyn’s post-Brexit immigration policy is a green card system. Anyone who successfully applied would have permanent residency rights.

Jeremy Corbyn appeared on the BBC's One Show tonight in a bid to allow voters to get to know him better

All EU citizens living here would be granted a card and applications would be open to anyone with ‘family connections, a job offer, relevant skills for employment and refugee or asylum status’.

Mr Corbyn’s advisers admit the proposal would require five entirely new IT systems.

On asylum, the document says: ‘We would overhaul our discredited current system in order to uphold our obligations to those fleeing war and persecution. Immigration is driven more by economic requirements of both migrant and host far more than it is regulated by systems of permit control. The numbers might go up or down but not as a consequence of these changes. We are not setting false, misleading, divisive targets.’

A Labour spokesman said: ‘After Britain leaves the EU, free movement of labour will come to an end. Labour will introduce fair rules and managed migration, based on the needs of our economy.

‘A number of discussion papers have been produced. This is part of one such document. It is not a statement of Labour policy, which is set out in our manifesto.’