PAUL di Resta no longer has a guaranteed drive Formula 1 but that doesn't mean the 30-year-old from West Lothian is slowing down. In fact, Di Resta, who drove in the colours of Force India between 2011 and 2013, must be one of the busiest men in motorsport. In addition to a day job racing for Mercedes in the Deutsche Tourenwagen Masters (DTM), as reserve driver for the Williams Formula 1 team he also knows he is next man up should anything happen to Felipe Massa or Lance Stroll. And on top of all that is his role as a pundit, helping drive Sky Sports' coverage of the event in the right direction.

As much as the Scot craves a chance to win back one of those coveted hot-seats at Williams when his current arrangement expires on December 31 - the veteran Massa only re-signed after Valteri Bottas' decision to move to replace Nico Rosberg at Mercedes - he is far from unhappy with the current arrangement. "I am very happy doing what I am doing and being part of Mercedes," said Di Resta. "It is no secret that returning to Formula 1, and driving for Williams, you know I would love to take that. But I am contracted for DTM and that is what I will be doing until December 31 this year. As for the future you never know where it is. Our career as drivers is relatively short, so you take it step by step."

It goes without saying that Di Resta's main priority, "his maximum focus" is with the DTM racing, a circus which begins in May, and where he is bidding to improve on last year's fifth place overall finish. "The focus is always to win the DTM championship, especially if you are in a works team," Di Resta says. "But ultimately I am also a reserve driver for Williams. It is a duty, a service I provide. And one that I enjoy. I enjoy keeping myself in the way with Williams and up to date with the latest technology in F1.

"It is wrong to compare them, they are two different animals," he added. "They have both got their benefits and they give you a totally different perspective on racing. The DTM is based on a touring car although it is more like a Formula car underneath. It is much more open for fans and families, they can get right up to the drivers. It is very much based on maximising its entertainment value and it gets great crowds, it has a great following.

"But being part of Williams is obviously quite special. They are very much a family-orientated business. You are obviously a stand-in but you want to be as professional as possible. I do various simulator sessions and I attend every meeting. At every Grand Prix I am as ready as I could be to get in that car if that opportunity arises but it is a bit of a strange role really. Obviously the team needs someone to be that reserve but they don't actually want to use that reserve."

Then there is his broadcasting work, of which he is perhaps a reluctant recruit. Much has been said about the fact that coverage of the sport will soon no longer be available on terrestrial TV with Channel 4 but Di Resta feels time has moved on.

"Sky do an excellent job - its production offers in-depth analysis for people who are huge fans of the sport," the Scot said. "The background tools they have got a world leading and you just have to look at the work they do in the Premier League in football as an example of what they can do. I love being part of it, even if I was always a bit unsure about it when I was a driver on F1. It felt like they were picking on you at times! Especially if the race hadn't gone well. But what they are trying to do, for the viewer back home, is get that best experience they can when they are sitting on the sofa. You are only a small part of a great team, whether it is sound, vision, production, edit. It is a bit like part of being an F1 team."

Di Resta is well placed to offer a driver's eye view and as such he cannot believe reigning champion Rosberg's decision to retire at the top aged just 31. In his absence, given the recent dominance of Mercedes, Lewis Hamilton is the clear favourite even if there has been buzz ahead of this weekend's season opener in Australia about a long-overdue resurgence by Ferrari and Sebastian Vettel.

"If I was 31 I wouldn't be anywhere close to retiring, especially if I had just won the World Championship," he said. "He had Lewis up against him and I think in terms of natural ability Lewis was that little bit quicker. He had to think that bit harder and maybe he just thought enough is enough. He had achieved his ultimate goal and I think if that was me I would probably try to build on top of that and use that momentum but everyone is different. He seems very relaxed about it and I respect that.

"But Lewis has to be a strong favourite, I guess he would be even if Nico hadn't retired," added Di Resta. "It is up to the other teams to try to stop Mercedes, to try to stop their domination."