He'll likely be given green light
A few years ago it would have seemed impossible, but now there is an expectation Martin McGuinness, the deputy First Minister, will attend a State banquet in Windsor Castle on April 8 hosted by the Queen to honour Michael D Higgins, the Irish President.
The banquet is on April 8. When an invitation goes out a decision will be taken by the Sinn Fein ard chomhairle.
One republican, speaking personally, said he did not see an obstacle "provided there is equality of symbolism".
Although Sinn Fein rejects the Queen's right to jurisdiction over Northern Ireland there's no dispute that she is the Queen of England, and therefore there is no problem in principle in attending a reception in Windsor.
One source said: "If it was up to Martin McGuinness, I believe he would go.
"When you bring the ard chomhairle into it, then that raises a question, but it seems more likely than not that he will go."