It may come as no surprise to some, but it seems that Simon Cowell is the kind of guy who holds grudges.

The X Factor judge and music mogul still hasn't forgiven Niall Horan for signing a deal with Universal Music instead of his own Syco label for his solo material.

He took a pop at the Mullingar native in yesterday's Sunday Mirror, criticising the chart position of his debut solo single 'This Town', which reached number 9 in the UK chart.

He said: "He probably would have had a Number One single if he'd stayed with me. But you know who does have a Number One this week? James Arthur. Very pleased he's back with us with a fantastic record. Hashtag loyalty."

Horan's single fared slightly better in the Irish charts, going in at number 6.