SINN FÉIN PRESIDENT Mary Lou McDonald has accused the British Prime Minister Theresa May of acting “in bad faith” and “playing a game of chicken with Irish interests”, in several UK media appearances this morning.

The Dublin TD appeared on ITV’s flagship programme Good Morning Britain this morning, defending Sinn Féin’s decision not to take its seven seats in Westminster and speaking about the threat Brexit poses to the peace process in Northern Ireland.

McDonald said that it would be “utterly reckless” for any British Prime Minister “to knowingly and cynically destabilize peace in Northern Ireland”, referring to May’s attempts to renegotiate the backstop, a clause in her Brexit deal that avoids a hard border on the island of Ireland.

Later, on BBC Radio 4 Today, McDonald said that ”the British government has played a game of chicken with Irish interests, they’re running down the clock”.

She added: “Brexit threatens to sunder the entire constitutional and political framework that accommodates the current stability and beds-down the peace process.”

Answering a number of questions about why Sinn Féin MPs don’t take their seats in Westminster in order to influence the direction Brexit is taking, McDonald told Good Morning Britain:

We have no business in your parliament… I’ve watched the sometimes very strange and exotic antics at Westminster throughout this whole Brexit process, and I am not convinced, and you won’t convince me, that by being in the middle of the melee we would be well positioned to protect Irish interests. I would not accept that.

She said that Sinn Féin participates in the Brexit debate through the European Union; both Mary Lou McDonald and Michelle O’Neill have met with EU negotiator Michel Barnier in relation to Northern Ireland and the backstop.

McDonald added that “as an observer” she thought that the Brexit debate in the House of Commons “has been about England in the first instance, which is fair enough, about English interests, which is also fair enough”.

Speaking to BBC News afterwards, McDonald called for a referendum on Irish unity.

“People across Ireland have an appetite for progress and should be given the opportunity to decide their own future through a unity referendum,” she said.

There are less than 50 days until the 29 March, the date by which the UK must leave the EU (barring an extension to Article 50, which looks increasingly unlikely).

The UK parliament overwhelmingly voted to reject Theresa May’s deal last month; she has promised to try to obtain concessions on the backstop in order to get the deal passed before the 29 March.

The EU has responded by saying that both the Withdrawal Agreement and the backstop are not up for renegotiation.

Yesterday, May said that if there is no breakthrough on the backstop by the 26 February, that another amendable motion would be tabled on 27 February, which could mean MPs vote on another series of options on what to do next.

In response to a question from MP Chris Leslie, May denied that putting a time limit on the backstop would be like putting a time limit on the Good Friday Agreement.