In a Facebook post the Foreign Secretary wrote: “Families across the country today watching Diane Abbott and Jeremy Corbyn account for a lifetime of sympathy for terrorism will be appalled.
“But it’s very simple: unless you vote for Theresa May and her Conservative team, Jeremy Corbyn will be your Prime Minister and Diane Abbott will be your Home Secretary 11 days from now.
“If you don’t want Jeremy Corbyn to be Prime Minister of this country, if you don’t believe he is equipped to negotiate Brexit, keep our economy strong or our nation secure there’s no safe way to vote Labour – wherever you live!”
Foreign Secretary Boris Johnson outside Carlton Gardens
Earlier Boris Johnson had taken to the social networking site to post a photograph of Mr Corbyn listening to Martin McGuinness speaking at a press conference.
Mr Johnson wrote: “I genuinely think it is important that people know this and a picture says it all.
“Jeremy Corbyn’s lies have been exposed by his own shadow home secretary. Just hours after Corbyn claimed he had never met the IRA, Diane Abbott says he did – and she disgracefully sought to defend it.
Foreign Secretary Boris Johnson's best gaffes Wed, July 20, 2016
Bumbling Boris Johnson's best gaffes and most controversial quotes.
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UK Foreign Secretary Boris Johnson said it would take him too long to apologise for the 'rich thesaurus' of rude comments and insults
“It is increasingly clear that Jeremy Corbyn will make up anything in an attempt to mislead voters. He’s pretending he didn’t support the IRA, just like he is pretending he won’t raise taxes and pretending he will replace our Trident nuclear deterrent.
“The risks of Jeremy Corbyn becoming Prime Minister, in charge of our Brexit negotiations and our security, are enormous.
“And Jeremy Corbyn would make Diane Abbott Home Secretary – putting a woman who refused to outlaw al-Qaeda and wants open door immigration in charge of our security and our borders. Only a vote for Theresa May and the Conservatives will stop this happening.”
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Boris Johnson's recent Facebook posts
Families across the country today watching Diane Abbott and Jeremy Corbyn account for a lifetime of sympathy for terrorism will be appalled
Foreign Secretary Boris Johnson
The comments come during something of a sustained attack from 52-year-old former Mayor of London on Labour and its leader in particular.
Just two days ago Mr Johnson slammed the left-wing leader in a press conference with his US counterpart Rex Tillerson.
Mr Johnson described Mr Corbyn as “monstrous” after he appeared to link terror to Britain’s foreign policy after the Manchester terror attack.
Rex Tillerson shakes hands with Boris Johnson (R)
He said: "Now is not the time to do anything to subtract from the fundamental responsibility of those individuals, that individual in particular, who committed this atrocity.
"And I think it is absolutely monstrous that anybody should seek to do so.”
However critics of Mr Johnson have pointed out that he linked terrorism and British foreign policy in an article in the Spectator one week after the London bombings in 2005.
Labour leader Jeremy Corbyn (C) with Diane Abbott (R)
In the comment piece he wrote: "It is difficult to deny that they have a point, the Told-You-So brigade.
"As the Butler report revealed, the Joint Intelligence Committee assessment in 2003 was that a war in Iraq would increase the terror threat to Britain.
"The Iraq war did not create the problem of murderous Islamic fundamentalists, though the war has unquestionably sharpened the resentments felt by such people in this country, and given them a new pretext.
"The Iraq war did not introduce the poison into our bloodstream but, yes, the war did help to potentiate that poison."