The North and Brexit tensions are likely to dominate discussions between the Taoiseach and UK prime minister later today.
Boris Johnson has been dogged by criticism in recent days over his response to an inquest finding that 10 people killed in shootings involving the UK army in the Ballymurphy area of west Belfast in 1971 were “entirely innocent”.
A spokesperson for Mr Johnson claimed he apologised on behalf of the British government in a phone call with the North's First Minister Arlene Foster and deputy First Minister Michelle O’Neill was dismissed by the families as a “third-party apology”.
Then, a letter of apology which Mr Johnson sent to the families’ solicitor as the UK's secretary of state Brandon Lewis made an apology in the House of Commons on Thursday was branded “unacceptable”.
Meanwhile, Micheál Martin last week expressed concern at reports the UK is considering introducing a form of amnesty on Troubles prosecutions.
He said any such proposal would represent a “breach of trust”, as it appears to scrap a key mechanism agreed by the UK and Irish governments and main parties in the North in the 2014 Stormont House Agreement.
The Taoiseach is also likely to want to discuss the ramifications of Brexit and the Northern Ireland Protocol on both trade and political tensions.
New checks on goods arriving at ports across the island of Ireland from Britain have impacted on trade.
However, with the Northern Ireland Protocol retaining the North as part of the EU for goods checks, unionists and loyalists have expressed anger at what they regard as a border in the Irish Sea and separation from the rest of the UK.
Protests have been ongoing across the North, with some resulting in serious disorder last month.
The violence was also attributed to anger at a decision not to prosecute senior members of Sinn Féin for alleged Covid-19 breaches at the funeral of Bobby Storey.
Unionism has been plunged into turmoil with DUP leader Arlene Foster forced to resign following an internal revolt, and UUP leader Steve Aiken also tendering his resignation.
DUP leadership contenders Jeffrey Donaldson and Edwin Poots have both pledged to increase opposition to the protocol, even if it risks collapsing Stormont.
Meanwhile, a pan-unionist legal challenge to the protocol is due to start being heard at Belfast High Court later.
Mr Martin and Mr Johnson will meet in a long-arranged meeting at lunchtime at Mr Johnson’s Chequers estate in Buckinghamshire.
A spokesperson for the Taoiseach said on Wednesday: “The lunchtime meeting, which was scheduled some time ago, is expected to cover the response to Covid-19, a range of issues relevant to peace and stability in Northern Ireland and the broader British-Irish relationship.”