The Taoiseach has said former UK Prime Minister Boris Johnson is better at selling books than being a politician.

On The Pat Kenny Show this morning, Simon Harris dismissed Mr Johnson’s claim that the US President had privately told him that he is ‘not really Irish’.

Mr Harris is due to travel to the White House next week to join President Biden at an event marking 100 years of relations between the US and Ireland.

Asked if he would press President Biden on the former UK leader’s claims, he said: “There are many very pressing and serious issues that, of course, I want to speak to the President of the United States about - including our diplomatic relations.”

“I think one question I definitely don't need clarity on is, does Joe Biden consider himself Irish.

“I think Boris Johnson is a person who seems to be very good at selling books and I hope he's certainly much better at that than he was at being a politician.”

File photo shows Joe Biden preparing to deliver a keynote speech in the grounds of Dublin Castle as part of his six-day visit to Ireland in 2016. Image: PA Images / Alamy

In his memoir, Mr Johnson claims that soon after taking office, President Biden privately told him his ancestors were not really Irish at all but English.

He says many people in the UK at the time were concerned about President Biden’s attitude to Brexit as he “made a big thing of being Irish by extraction”.

He then claims that President Biden “completely disarmed” him by telling him that his ancestors were not Irish but rather an old seafaring family from Kent.

US President Joe Biden arrives at St. Muredach's Cathedral, Ballina, County Mayo. 8/4/23 Image: Official White House Photo by Katie Ricks

President Biden has been vocal about his Irish roots and his love for Ireland ever since he first entered politics.

During a visit to Ireland in April of last year, he visited the home of his ancestors in County Mayo and named himself a ‘Son of Ballina’.

His great-great-great grandfather, Edward Blewitt, left Ballina for the US during the Great Famine.

At the North Mayo Heritage Centre, he was gifted a brick from the original Blewitt home.

He also spoke with the family that now operates a shop on the site of his ancestral home.