The United Kingdom left the EU in January but the two sides are trying to clinch a deal that would govern nearly a trillion dollars in annual trade before informal membership - known as the transition period - ends on 31 December.
Biden's win in the U.S. presidential election has changed the international context of Brexit: The United Kingdom's most powerful ally will now be led by a man who favours a Brexit deal and relishes his Irish heritage.
"He is very committed to the Good Friday Agreement," Martin said of Biden. "Particularly in relation to Brexit, he would favour obviously a deal between the European Union and Britain."
"And I think that's where, if I could respectfully say it, that's where the British government should head, in that direction, in my view. It should knuckle down and... get a deal with the European Union," Martin told BBC radio.
I’ve had a warm and engaging call with US President Elect @joebiden He brings tremendous knowledge & understanding to his new role, and has a great love for his Irish heritage. He underlined his commitment to the Good Friday Agreement & we spoke of importance of multilateralism..
— Micheál Martin (@MichealMartinTD) November 10, 2020
No deal Brexit would be ruinous
A tumultuous "no deal" finale to the United Kingdom's five-year Brexit crisis would sow chaos through the delicate supply chains that stretch across Britain, the EU and beyond - just as the economic hit from the coronavirus pandemic worsens.
"It is crucial that we get a deal - in my view: where there is a will there is a way," Martin said, adding that a no-deal would be "ruinous" for the United Kingdom.
"I actually believe that Boris Johnson wants a deal. I think his gut instinct would favour a deal. The politics of what is happening within Britain is something that may influence issues," Martin said.
But the clock is ticking: the talks are now likely to go beyond yet another Brexit deadline - this time 15 November - though negotiators are racing to clinch a deal that would allow enough time for ratification before it kicks in on 31 December.
Speaking of Biden, Martin said his affinity with Ireland was clear and that he wanted nothing to hurt the 1998 Northern Irish peace deal that ended three decades of sectarian violence.
"He has a deep affinity to our country, and it's wonderful to hear that. And his grandfather had a particular influence on him, so he understands the Irish probably better than the Irish themselves," Martin said.
"So I think he's very comfortable with us. But I have no doubt too that he sees the United Kingdom as a very significant partner to the United States."
Reporter: "Mr Biden, a word for the BBC?"#PresidentBiden2020: "BBC? I'm Irish..."
— Chris Shaw (@The_ChrisShaw) November 7, 2020
Now, what was that about the Internal Markets Bill...? pic.twitter.com/Yx68BTfdfL
Martin said Johnson's Internal Market Bill had raised concerns about how far the EU could trust him - including doubts about the solidity of a potential trade deal.
Housing Secretary Robert Jenrick said Britain would not compromise on its sovereignty but that the government hoped for a deal in the days ahead.
"We hope that in the days ahead, admittedly, time is short, but in the days ahead, both sides will be able to reach agreement and the EU will show some further flexibility in those respects," he told the BBC.
(With Wires)
