Australia’s loss might soon be England’s gain judging by the county cricket form of Sydney-born batsman Sam Robson.

The 23-year-old opener continued a brilliant start to the season on Friday with an unbeaten double century in Middlesex’s clash with Warwickshire at Edgbaston.

His 215 not out in Middlesex’s first innings was his highest first-class score, and lifted him above fellow Australian and Middlesex opening partner Chris Rogers as the competition’s leading run-scorer.

Robson has played for Australia at under-19s level but has been with Middlesex since 2009 and will qualify for England residency next year.

He also holds an English passport, with his mother born in Nottingham.

There are conflicting reports as to whether Robson wants to commit to England or prefers to hang out in the hope of an Australian call-up.

But he stressed after his latest knock he was focused on his county cricket career.

“I don’t think there is a realistic chance of Australia picking me at the moment and, while there have been opportunities to play first-class cricket in Australia, I wouldn’t want to jeopardise my position in county cricket,” Robson said.

Robson has 579 runs from his seven county innings so far this year, more than Phil Hughes managed in 17 innings for Worcestershire last season.

The former NSW under-17s player averages just under 40 in first-class cricket.

Middlesex declared their innings at 5-428 after a rain-interrupted second day of their match, with Rogers scoring 33.