Respect for unionist aspirations is a requirement of the Good Friday agreement. If we are to deepen friendship on our small island that respect should be written in our hearts. Parity of esteem, which requires equal respect for nationalist aspirations, must work in both directions.

As a former Irish diplomat, I come from a different tradition from unionism, but it is with that awareness that I offer the following thoughts.

I am conscious that most of the people of Northern Ireland voted against Brexit and that there are many strands of unionist opinion on the issue. However, at this important moment in the Brexit negotiations the focus is necessarily on the Democratic Unionist party, given its pivotal role in support of Theresa May’s government. I’m sure there is serious strategic thinking going on within the party. No doubt they are asking themselves, for example, whether and how to respond to the many voices from the Northern Ireland business community who are prioritising the need for compromise. However, at the same time, some voices in the DUP have stepped up appeals to a traditional “no surrender” mentality.

I understand that the violence directed at the unionist community during the Troubles helped to stoke a defensive mentality, even if I have not suffered as they and others did. However, it seems to me that, for four important reasons, any temptation to adopt a simple “no surrender” approach at the present time is neither necessary nor sensible.

First, rejecting any compromise can sometimes make sense in a negotiation in which there is no firm timeline. Parties from both communities in Northern Ireland have often played hardball in circumstances in which the alternative to agreement was stalemate. However, the UK has decided that it will leave the EU on 29 March next year. Thus, in this case, the alternative to compromise would not be stalemate, but a hard Brexit. That would be in nobody’s interests, least of all in the interests of the UK or of its constituent parts.

Second, on the British side the decision on what compromises to strike will eventually be made by the UK government. I cannot possibly know what the precise limits of London’s flexibility will be. Nor am I suggesting that May would do anything other than take strong account of unionist concerns. However, she will be negotiating in the interests of the UK as a whole, aware that her country has a profound interest in reaching an overall compromise. In a negotiation, it generally falls to those sitting at the negotiating table to decide whether and how to cut a deal.

Third, an insistence that one will never surrender is normally linked with a passionate belief in maintaining the status quo. However, the vote in favour of Brexit, whatever the outcome of the negotiations, will inevitably bring great change. A strong case can be made that the harder the Brexit, the more significant the change for Northern Ireland will be. A hard border on the island of Ireland, far from making the union more secure, would give momentum to the constitutional question as provided for in the Good Friday agreement. I expect many unionists understand that. Maintaining a soft border on the island is the best way to remain as close as possible to the status quo.

Finally, it only makes sense to refuse to surrender if you are actually being asked to surrender. While I respect those in the DUP who will disagree, the EU is not asking anyone to capitulate. Its negotiators have no wish to upset the balances of the Good Friday agreement or to undermine the unity of the UK. The EU has never called into question that Northern Ireland is part of the UK. Nor did it propose a border in the Irish Sea even if that term is now commonly used to describe its original proposal. Michel Barnier has indicated his willingness to make these points even clearer.

The EU member states and institutions understand, far more than many in London and Belfast allow, the complexity of Northern Ireland. They understand the equilibrium of the peace process, not just because they listen to Dublin, but because they have listened to successive British governments and to Northern Irish political parties and MEPs over many years. Successive first ministers and deputy first ministers have been welcomed to Brussels with open minds and open arms. The EU has always responded to the people of Northern Ireland with generous political and financial support.

I understand that many unionists are not comfortable with the EU’s approach. But the need to find new arrangements arises from the reality of Brexit. If in the coming weeks there is to be a satisfactory agreement for everyone, everyone will need to make compromises. The issues should be de-dramatised.

• Bobby McDonagh was Ireland’s ambassador to the UK from 2009 to 2013