Australia's cricket team was mired by another controversial moment on British soil on Wednesday after a star player was not given out in dubious circumstances.

The Aussies, taking on Scotland in the first match of their T20 series, were 113-2 in the seventh over when Scottish spinner Mark Watt readied himself to bowl at batter Josh Inglis.

However, instead of running up towards the crease, the bowler launched his trademark 24-yard delivery, named the 'long ball', in which he releases the ball from well behind the crease to surprise the batter.

Inglis, who had taken guard for the delivery, pulled away as the ball bounced on the turf. The delivery went on to clip leg stump and the Scots strongly appealed for a dismissal.

Yet umpire David McLean signaled 'dead ball', giving Inglis a lifeline.

According to MCC Law 20.4, an umpire should call a dead ball if the batter had adequate reason for not being ready and made no attempt to play the delivery.

Watt was denied a similar wicket at the T20 World Cup earlier this year when he dismissed Oman batter Khalid Kail with his 'long ball'. The umpire signaled 'dead ball' on that occasion too.

'It's just trying to rush (the batters),' the 28-year-old has previously said when explaining his unique delivery.

'By the time I've let it go, the batsman looks up and the ball's halfway down the wicket.'

'(It's effective because) it's the element of surprise that he bowls it,' Scotland all-rounder Michael Leask said earlier this year.

'It's also how good he is at holding his length, it still spins. It's just that fraction longer.

'Man, it's horrible to face, even for us in the nets.

'You know it's coming every two minutes. He does it a lot.'

Australia won the match by seven wickets and Inglis finished the game unbeaten on 27 runs from 13 balls.