Darren Clarke sacks the caddie who helped him win the Open

The Ulsterman, who had employed Mulrooney for less than a year, took the decision after missing the halfway cut at the HSBC Abu Dhabi Championship on Friday.

Clarke had opened the first event on the European Tour’s Middle East Swing with a level-par 72 but followed that with an 81 to finish well down the field.

Now 43, Clarke has struggled with his game since recording his memorable major triumph in Kent, where he claimed the Claret Jug by three shots from American duo Dustin Johnson and Phil Mickelson.

He hasn’t managed a top-ten finish since that victory and in the PGA Grand Slam of Golf in Bermuda towards the end of last year he was left trailing in the wake of the other three 2011 major winners.

Keegan Bradley, the USPGA champion, finished 13 shots ahead of Clarke, who was also 12 and nine shots respectively behind Charl Schwartzel, the Masters champion, and US Open title-holder Rory McIlroy.

According to ISM, Clarke’s management company, the split with Mulrooney is amicable and the player will spend some time weighing up his options for a replacement.

Having decided not to play in either Qatar or Dubai, Clarke’s next competitive outing will be the WGC-Accenture Match Play Championship in Arizona at the end of February.

Mulrooney took over as Clarke’s full-time caddie after the former Ryder Cup player won the Iberdrola Open in Majorca last May.

The pair came close to breaking up after it was claimed they had a a furious disagreement on the Sunday at the Scottish Open at Castle Stuart, but they were back on the same wavelength as their partnership worked a treat the following week.

Speaking after his spectacular success at Sandwich, Clarke said much of what he achieved in the world’s oldest major was down to Mulrooney’s timely assistance and his ability to calm him down when it mattered the most. “John has been fantastic,” said Clarke at the time. “When I went to Mallorca seven weeks ago, he was meant to caddie for David Howell, who got injured, and then he was supposed to caddie for Maarten Lafeber and he got injured, too.

“Ricky Roberts was meant to caddie for me but he went to the induction of Ernie Els into the Hall of Fame, which is fine. I ended up with John working for me, which was wonderful. He’s a very good guy, very quiet and a little different, but a very, very good caddie.”

It has been rumoured that the pair had another bust up in Bermuda and now Mulrooney, who had worked earlier with Miguel Angel Jimenez and Jose Maria Olazabal, has found himself seeking a new employer just four events into the new European Tour season.

Billy Foster, now with Lee Westwood, was Clarke’s caddie for a long time, while he also had Phil Morbey, better known as Wobbly, on his bag for a spell as well.

Clarke has been making a number of changes in a bid to recapture his form. For instance, he has employed the England rugby team’s sports scientist, Jonathan Bloomfield, as a full-time fitness advisor.

Bloomfield, a fellow Ulsterman who is based in Belfast and has also worked with the Ulster rugby team, was recommended by Steve McGregor, Lee Westwood’s fitness guru.

“I am a lean, mean fighting machine,” said Clarke before teeing off his new season in the Volvo Golf Champions event at Fancourt in South Africa a fortnight ago. “My career has been extended by winning the Open and I just thought ‘enough is enough’ – it’s time to get myself in better shape.

“Jonny’s got me doing all sorts in the gym, having my eyes checked out, nutrition etc. Therefore my alcohol consumption is taking a massive dint... it’s currently down to zero.”

Ironically, South African Louis Oosthuizen, the man who preceded Clarke as Open champion, also changed his caddie shortly after becoming a first-time major winner. Zack Rasego, who was at Oosthuizen’s side as he lifted the Claret Jug at St Andrews in 2010, is now working for Branden Grace, the young South African who recently recorded back-to-back wins on the European Tour.