Cricket: Brendon McCullum emerges as leading candidate for England test cricket coach

One of New Zealand's greatest ever cricketers has suddenly become the leading candidate to coach one of the Blackcaps' biggest rivals.

Having previously been linked to the white-ball vacancy with England, Newshub sources have confirmed Brendon McCullum has emerged as the favourite to become the next England test coach.

Chris Silverwood left the role in February in the aftermath of their 4-0 Ashes defeat in Australia, with Paul Collingwood named as caretaker. The England and Wales Cricket Board then invited applications for separate test and white-ball coaches.

It's understood McCullum is one the final candidates, alongside former South African cricketer Gary Kirsten and Australian Simon Katich.

On Tuesday (NZ time), interviews for both the limited overs and test roles and Newshub can reveal McCullum had several formal discussions with the England and Wales Cricket Board (ECB) during that time.

McCullum's only coaching experience to date is in the Twenty20 format. He's currently with Kolkata Knight Riders in the Indian Premier League.

But it could be a case of who he knows, rather than what he's coached.

He has a great relationship with England's one-day international and T20 captain Eoin Morgan and currently coaches Sam Billings at the Knight Riders , who's regarded as a captain in waiting.

He's also close mates with the ECB's new director of cricket Rob Key, who will essentially make the final decision on the appointment.

There's a slim possibility McCullum could be in charge for the first test against the Blackcaps at Lord's next month, although IPL commitments may prevent that.

A formal announcement is expected later this week.