Democratic Unionist Party (DUP) leader Gavin Robinson has warned his party has put a “marker” down at Stormont to block Sinn Féin spending money on “pet projects”.

It follows the decision by Infrastructure Minister Liz Kimmins to approve £150,000 for Irish-language signage at Belfast’s new Grand Central Station.

A row over the Irish language around the executive table is nothing new but this one has been simmering for some time.

Sinn Féin has accused the DUP of blocking the executive from resolving a funding crisis for cross-border Irish language services, which are facing a £650,000 cut.

The finger of blame is being pointed at DUP Deputy First Minister Emma Little-Pengelly for refusing to allow the matter to reach the executive.

So this latest row over Irish-language signage at Belfast Central Station has added another pressure point.

In an email to his supporters over the weekend, the DUP leader said the signage decision was now being challenged around the executive table.

It is understood DUP Communities Minister Gordon Lyons has posed a series of questions about the move in a letter to the infrastructure minister.

Last week Little-Pengelly criticised the decision, claiming “much of the £150,000 will be used to rip out new signs” to “drive forward a political agenda” by the infrastructure minister.

She also questioned spending the money at a time when the executive financially was in a “very difficult place”.

But in announcing the extra funding, Kimmins said it was a “hugely positive development” which reflected the “thriving Irish language community”.

She also confirmed her decision had passed an equality screening exercise which showed it would have “a minor positive impact”.

It may come down to whether or not the decision by the infrastructure minister to approve funding for the signs should have been subject to wider executive approval.

Robinson believes it should.

“This is clearly a controversial matter and our ministers will use their position at the executive table to not only get to the bottom of how the decision was made but put a marker down that public money cannot be used to further Sinn Féin’s pet project,” the DUP leader said.

Whether the decision can be taken by a single minister depends on whether it is considered “controversial” and/or cross-cutting, in other words whether it falls under the purview of multiple departments.

History tell us it may be a judge and not a minister who decides, if we reach that point.