Speaking at the SNP conference in Aberdeen, Mr Blackford hit out at the Labour leader, claiming he failed to provide a strong opposition to Theresa May’s plans for a hard Brexit.
He also argued that Labour was “colluding” with the Conservatives, calling the party’s stance on Brexit “week and confusing” and “completely dangerous”.
He said: “The Labour Leader’s failure to recognise the critical need for these nations to remain in the Single Market – is ludicrous.”
Mr Blackford confirmed to activists that SNP MPs will vote in favour of the UK staying in the customs union and the single market once UK leaves the bloc, which will be highlighted in the EU Withdrawal Bill upon its returns to the House of Commons next week.
The SNP Westminster leader added: “Labour must join with us and give full support to staying in the single market and the customs union to mitigate against the risks of a hard Brexit.
“Anything less and Labour will be just as responsible as the Tories for the damage that will follow.”
Mr Blackford also lashed out Mrs May’s “cruel, callous and chaotic Tory Government”, saying that indecisiveness within her cabinet over Brexit matters made her one of the “weakest” prime ministers for a generation.
He added: “Not only is the current Prime Minister a slave to the Brexiteers in her cabinet, she is constantly choked by the grip of her shady deal with the Democratic Unionist Party.”
The SNP MP issued a dire warning to that the UK would “pay a price due to the intransigence of May’s Government who have been hijacked by their own right wing Brexiteers”.
He added that even though Scotland “remains tied to Westminster for now”, SNP MPs would “take on the Tories in defence of our national interests”.
Mr Blackford made his speech ahead of key debates surrounded the EU Withdrawal Bill next week, adding that Mrs May had an “opportunity to change course, to finally face the reality that lays before her and stop a hard Brexit”.
Addressing issues around UK’s customs union, he said: “I can confirm to you all today that we will vote to keep Scotland and the UK in the Customs Union and the single market.
“We will vote to secure jobs, the economy and EU citizens’ rights in Scotland.
“We will vote to stay close to our European partners and allies, not to build walls based on empty promises of trade deals with a President more interested in trade wars.
“Theresa May must now stop her charade and deliver in the interests of all across the UK.”