Boris Johnson today urges voters not to inflict a Friday the 13th 'nightmare' on Britain by handing Jeremy Corbyn the keys to No 10.

The Prime Minister's late Election plea comes as The Mail on Sunday can reveal that the Labour leader has been named as the worst antisemite on the planet by the world's leading Nazi-hunting organisation.

The Simon Wiesenthal Centre warns that Corbyn would turn Britain into a 'pariah state' if he wins Thursday's Election.

The Mail on Sunday can reveal that the Labour leader has been named as the worst antisemite on the planet by the world's leading Nazi-hunting organisation. Mr Corbyn is pictured above campaigning in Swansea, Wales

The Prime Minister's late Election plea comes as The Mail on Sunday can reveal that the Labour leader has been named as the worst antisemite on the planet by the world's leading Nazi-hunting organisation, The Simon Wiesenthal Centre

In an astonishing escalation of the row which has ripped Labour apart, the human rights body said: 'No one has done more to mainstream antisemitism into the political and social life of a democracy than the Jeremy Corbyn-led Labour Party.

'Members and staff who have dared to speak out against the hate were purged, but not those who declared 'Heil Hitler' and 'F*** the Jews.'

Rabbi Marvin Hier, the head of the centre, told this newspaper: 'If it wasn't for Winston Churchill and Britain leading the fight against Nazism in the Second World War who knows if the Allies would have won?

The PM writes that if the Conservatives do not win, the 'nightmare alliance' of Mr Corbyn and SNP leader Nicola Sturgeon would become a reality on Friday the 13th. He is pictured above in Wigan

'Britain was at the forefront of defeating Hitler and now, on the 75th anniversary of the liberation of Auschwitz, the person who wants to sit in Winston Churchill's chair at No 10 is fostering antisemitism. If Mr Corbyn wins he will make Britain a pariah on the world stage. It will be a disaster for democracy.'

Established more than 40 years ago to combat hate, the US-based Simon Wiesenthal Centre is named after the death camp survivor who helped track down more than 1,000 Nazi war criminals, including Adolf Eichmann, a key architect of the Holocaust.

Rabbi Marvin Hier, the head of the centre, told this newspaper: 'If it wasn't for Winston Churchill and Britain leading the fight against Nazism in the Second World War who knows if the Allies would have won?'

A Labour spokesman said last night: 'This ranking is ridiculous and grossly offensive. Putting Jeremy Corbyn at the head of a list containing neo-Nazi synagogue shooters is a transparent political attack and has nothing to do with tackling antisemitism.'

The devastating intervention comes as Tory strategists mount a concerted push for votes in the closing stages of the contest.

Emulating the techniques used by the successful Vote Leave campaign in the 2016 EU referendum, the party yesterday launched a £100,000-a-day social media blitz to hammer home its core political messages and plans for tough post-Brexit immigration policies.

In a letter to the nation – published opposite – Mr Johnson says Mr Corbyn's immigration policy would 'put even more pressure on the NHS and our other public services'.

The Prime Minister argues: 'He does not just want to keep free movement with the EU – where even murderers have free movement rights – but he wants to extend it to the whole world so anyone from anywhere can come here any time they like.

'And there would be nothing you could do about it.'

He writes that if the Conservatives do not win, the 'nightmare alliance' of Mr Corbyn and SNP leader Nicola Sturgeon would become a reality on Friday the 13th.

As the campaign for one of the most significant Elections since the Second World War approaches its climax:

The final Mail on Sunday Deltapoll gave the Tories an 11-point lead over Labour;

More details emerged of the tough immigration systems planned by the Conservatives, including the digital tracking of migrants;

Senior spies warned Mr Corbyn about his approach to foreign policy as it emerged he had dismissed Islamic State as 'no threat' to the UK

Mr Corbyn also became embroiled in a row over Russia's alleged involvement in the leaking of NHS documents he brandished in the campaign;

Labour high command was thrown into panic after its private research suggested that large swathes of its 'red wall' of seats in the Midlands and the North could fall to the Tories;

Labour frontbenchers including Keir Starmer and Angela Rayner started jockeying for an expected leadership race;

The Brexit Party row over Nigel Farage's refusal to withdraw from the Election escalated as former candidate Annunziata Rees-Mogg said that Mr Farage's career was set to 'end in failure';

Mr Johnson was revealed to have phoned US President Donald Trump before his trip to the UK last week to urge him not to do anything to damage his campaign – and persuaded him to pull out of an interview with Piers Morgan;

Last night, Defence Secretary Ben Wallace criticised Mr Corbyn over his use of leaked documents, saying: 'Labour's desperation has led them directly into the hands of the Russians. Putin must be laughing at how easy it has been to hook Labour's useful idiot.'

Meanwhile, details emerged of Tory plans for a points-based immigration system after free movement ends.

It will split migrants into three categories: those of exceptional talent who will receive fast-track entry even without a job to go to; skilled workers who have enough points and a job offer; and 'sector-specific' low-skilled entrants who will be on time-limited visas, ending indefinite leave to remain.

A digital tracking system will be introduced by 2022, allowing migrants to be counted in and out of the country for the first time, which Tory advisers say will improve enforcement.

Meanwhile, a Bank of England-style reporting system will advise the Government on how to lower immigration while filling gaps in the labour market. It aims to ensure that the Home Secretary has the information needed to make decisions rapidly.