WATCH: Dylan Hartley sent off for absolutely sickening attack on Sean O’Brien

Dylan Hartley just can't help himself.

It may have been a while since the England hooker found himself on the naughty step but he will be stewing there for at least two months after a quite deliberate and disgusting swinging arm assault on Sean O'Brien. On as a second-half substitute for Northampton Saints, the England captain lasted all of six minutes on the field. He was helpless to stop O'Brien crashing over for a vital Leinster try and set out to, quite literally, deliver a leveller to the Ireland flanker. It was gruesome, awful stuff and it left O'Brien in a heap. Referee Jerome Garces sent the replays upstairs for a review but told the TMO, "For me it is clear, a swinging arm... It's a clear red card." Hartley jogged off and England head coach Eddie Jones - the man that revived his Test career - was fuming up in the stands. O'Brien, meanwhile had to go off for a Head Injury Assessment. He did not return. Hartley has a long, long list of offences and has racked up almost a year in bans from rugby for separate, ugly offences. In May 2015 he was banned for four weeks after a headbutt on Saracens' Jamie George while he got a straight red card for this incident involving Leicester Tigers' Matt Smith in 2014: A nasty piece of work. This will certainly damage Hartley's chances of claiming captaincy of the 2027 British & Irish Lions. Diarmuid Connolly makes his long overdue GAA Hour debut and talks to Colm Parkinson about everything from the black card to his rivalry with Lee Keegan and how he honed the ability to kick accurately with either foot.