Jack Farthing, who plays Ross Poldark’s troubled and complex adversary George Warleggan, describes mixed emotions about the drama coming to an end. 

"I am a bit of a one for nostalgia and I have been languishing in the fact this is the final series - it is odd but also exciting for a number of reasons. Firstly because it has been a successful show and we are all so happy and proud of what we have achieved. But also because we have an amazing series this year - it's solely based on Debbie Horsfield’s writing and it has a different feel to the other series - it's very exciting. As much as it has been strange and sad it has also felt like we’ve all wanted to really nail it."

Jack talks about the traumatic end of last series and where we find George at the start of this final series.

"Losing Elizabeth (Heida Reed) at the end of last series was extremely traumatic for George. We pick up this series a few months afterwards. He is apparently back to normal, at his desk hard at work but crucially refusing to talk about anything - he doesn’t want to hear her name, pictures of her are being taken down from the house, he is getting on with his life. However, gradually you become aware that he is not anywhere near as calm as he appears, he is suffering inwardly and apocalyptically. George has been totally changed forever by what happened at the end of the last series."

How does George fair emotionally in the wake of losing everything he ever dreamed of in one fell swoop?

"At the beginning he is telling everyone he is fine, which is a commonplace response to a traumatic event, to brush it all under the carpet. But as soon as he is triggered and brought back to it, it is catastrophic for him and is a challenge like nothing he has ever faced. So he is more wounded and less stable than he has ever been. Elizabeth stays with George, it's like she is dead but her presence is as potent for him as ever - even when she is unmentionable she is still his moral compass and the reason for certain actions he takes this series. You see moments where he is looking at her picture and he is trying to see things through her eyes, he can still hear her and she guides him, and whereas he may have railed against that in the past it is like music to him now."

Jack reveals that filming this final series of Poldark has been the biggest acting challenge.

"The most challenging work I’ve done in the past five years is all in this series. George is grieving in a particular and dramatic way. There are climaxes to his sadness and some of them were pretty challenging to film. There are moments where Dwight (Luke Norris) takes him on as a patient and in a modern and intelligent way goes through talking therapy with him. Others are trying to lock him up or drown him, but Dwight realises that what he needs to do is talk to George, get inside it psychologically and make George confront it rather than allow him to continue to evade it.

There is a particular moment when we go back into the bedroom where Elizabeth died and Dwight makes George remember it, and that was really heavy. We filmed so much in that bedroom set that when we walk into that room my heart just sinks. I did a lot of running around in my nighty this series, which in the chilly weather is also a challenge. Standing on the edge of a cliff in a nighty is not all that much fun."

Jack did a great deal of preparation for his complex role this series.

"I did a lot of research to try and make the work I was doing feel real and authentic. I spoke with some psychologists about grief and the aftermath and the range of reactions they had seen. I found this wonderful woman called Dr. Jacqueline Hayes and we talked about complicated grief versus psychotic reactions, as George isn’t suffering from a mental illness, he hasn’t got a previous history with that and he is not psychotic, but it is very complicated post-traumatic grief and the range of reactions people have is infinite.

Around 60 percent of people who are grieving for a lost loved one have some form of contact with them, be that hearing, talking, smelling or touching, it is normal - people think they are going mad but they are just grieving, so it was important for me to hold on to that. As much as this is a dramatic and quite extreme version of that, it was so interesting to learn about it and try my best to make it feel authentic."

Jack has enjoyed playing a role that continues to evolve and shock audiences. He reveals that people will see a very surprising and unseen version of his character this series.

"What I think Debbie has done amazingly well is to surprise people. She hasn’t felt like she always has to sit back into the moulds of characters we established in series one, and that is probably one of the greatest strengths of all of the characters but particularly with George. People will have him labelled as a ‘baddie’ so it is interesting when you find yourself feeling sorry for him or momentarily sad for him. People are different all the time and so the audience don’t mind if you act unexpectedly, they’re still going to believe who you are, they’ll just think you are behaving out of character, which is what humans do. So I have embraced the ambiguities and they are by far my favourite things, those moments of thinking, would he do that…?’

Ross and George come up against each other for the final time this series. Might be hope for any reconciliation between them?

"Ross and George can see each other more clearly through the emotions of their antagonism towards each other. It is not that they are suddenly going to be friends or that they agree about anything but it is just that they can share a little bit more and that is possibly because they have both lost Elizabeth.

They saw each other at these very low ebbs at the end of last year and you bond over that experience, whether you like it or not. They know more than they let on about what the other might be feeling. But also along with that there are still moments of total fury and winding each other up. Ross more than anyone has the balls to come into the house and talk about Elizabeth, which is totally taboo and whilst he is not necessarily doing it with malice, inevitably it causes problems."

Jack reveals he will miss stepping into George Warleggan’s shoes every year and tells us about a special keepsake he has taken from set.

"I will miss playing George. I have been so lucky, it has been a lot to find and play with, and you take that for granted when you do that. Now it is coming to an end I realise how lucky I have been, playing this role and the quality of the people who make this show is incredible and are so friendly… it has been a total dream. I will miss telling his story but I am happy with how it has gone, and hopefully this series lives up to what it should.

I have a George Warleggan costume already hanging in my wardrobe at home. A jacket, britches and waistcoat that were all made for me - I spent the whole series in them and I just love them. It is pure nostalgia, although maybe one day I’ll wear it for a fancy dress party."