The Greenock-born actor, who played DI Steve Arnott in the hugely-popular BBC series, was asked during an interview with ES Magazine if creator Jed Mercurio is planning a seventh series.
“The genuine answer is that we don’t know,” he said. “But that’s nothing new. Jed always takes time away from it.
“I think what I would say, the two things I would say, is that the idea that I would never work with all the guys again together would be heartbreaking.”
The 37-year-old also said he understood some fans who felt let down by the season six finale when the identity of arch villain “H” was finally revealed.
He said: “You’ve got to respect people have invested so much in this thing and everybody has a different version of their ending.”
Line Of Duty has become the UK’s most-watched drama series of the 21st century so far, after official ratings showed this year’s season finale had a TV audience of 15.24 million.
This is 80,000 higher than the previous record, which was set by an episode of Heartbeat on ITV back in February 2000 which had a TV audience of 15.16 million.
It means the BBC One police thriller is now the highest-rated TV drama series since March 1999, when an episode of ITV’s A Touch Of Frost won an audience of 15.83 million.