'We're so sad she's not going to be with us': Tramlines boss Timm Cleasby on Sheffield festival's tributes to Sarah Nulty and how move to Hillsborough Park is his biggest challenge yet

Timm Cleasby, operations boss of Sheffield's Tramlines music festival which returns on Friday for its 10th edition, is recalling his final conversation with Sarah Nulty, the event's director who died tragically from cancer aged 36 at the end of June.

"She wanted to discuss things; we'd got things we needed to sort out and because she was very poorly, she'd had a lot of time off," he says. "She was dedicated to getting things finished. Right up until she was admitted to hospital, really."

The loss is still raw and Timm pauses to gather his emotions. Sarah's lively nature, vibrancy and energy will be sorely missed at this year's Tramlines, the biggest outing yet, taking place for the first time on an expanded, 40,000-capacity site in Hillsborough Park, with major headliners Noel Gallagher, Stereophonics and Craig David topping the bill. But the show must go on, above all for Sarah - the team has rallied round to make sure it is the success she envisaged.

"It's what she would have wanted," he says. "I know that's quite a clichéd thing to say but she was so passionate about the festival, particularly this year because it's a 10-year celebration. She was keen to make it a special event. Between us we just want to carry that on. It's not something we take lightly; we take on that responsibility with a lot of commitment to her. We're so sad she's not going to be with us. Having to use the past tense is very difficult."

Sarah carried on working for as long as possible, and told her Tramlines colleagues straight away that she was unwell.

"I think she had to. It was going to take some time for treatment, and for her to get her head around what was happening in her life. We knew when she was diagnosed. And we knew she was poorly before that, but they thought it was a lot of different things, so when she got the diagnosis it was a massive shock. She was quite keen that it wasn't a big public thing and it wasn't told to everyone. She was private in that way."

She did not disclose the full details of her illness, which was diagnosed in March. "I don't think she ever shared that precise information with us. She just told me that it was bad, and it was everywhere. She'd got trouble with her breathing, and they thought it was something else. She'd been in and out of hospital having tests and things."

Much thought has been given as to how Sarah should be remembered at the festival. A private bar - Nulty's Bar - will be set aside for friends and family needing a quiet moment to reflect, and on Sunday, before Craig David performs, a memorial video will be screened on stage with poignant pictures and footage. David was to be one of Sarah's highlights, Timm says.

"After that we're going to do a minute's applause to celebrate her life. We thought about doing a minute's silence, but Sarah wasn't a quiet girl so it was kind of doing her an injustice."

In addition, festivalgoers will be encouraged to support a hashtag - #bemorenulty - that has emerged on social media. "We quite like that. She was a lovely person. She was hardworking and had a real positive attitude. We can all aspire to be a bit more Nulty in our life."

Bags and T-shirts with a 'Be More Nulty' logo, designed by Tom J Newell, are being sold at the festival site, and online via Drop Dead Clothing, with profits going to Weston Park Hospital's ward two and Cavendish Cancer Care.

A decision on whether a stage should be renamed will come later. Timm is also talking to the council about what can be done 'wider within the city' to pay tribute to Sarah on a more permanent basis. "There's a couple of things we're discussing."

Tim's role - operations director - involves making sure the festival is delivered according to plan, and that arrangements are in place for public safety.

Is moving Tramlines to Hillsborough Park his greatest challenge yet?

"Oh, completely. I've worked some big gigs in the past, but this is the biggest one I've had to organise. Finding the right amount of kit has been interesting, and we're managing the local residents as best we can - we know there's going to be some impact on their lives, but we've been working really hard to minimise the disruption."

Litter pickers are being deployed on local streets, there will be measures to cope with car parking and toilets are being provided outside the site itself. "I think we've got there and it's looking good."

Timm, 46, was originally asked to lend his expertise to Tramlines because of his status as Arctic Monkeys' tour manager, a post he held for five years. Drummer Matt Helders helped to launch the festival when it was a free, council-funded venture in 2009, encompassing a main stage on Devonshire Green and city centre indoor venues. The aim was to create a buzz in summer, previously a quiet time after students had left at the end of the university year.

"He wanted someone he trusted to make sure he was putting his name to something he could proud of."

Timm was the stage manager initially, then his duties grew. Sarah was managing The Harley on Glossop Road when she was approached to help organise the first Tramlines.

A lot has been learned from those early days on Devonshire Green, and the main stage's subsequent relocation to the Ponderosa park in Upperthorpe - mainly about noise, and the way a large crowd moves, which determines how walking routes should be mapped out.

Arctic Monkeys are on the road again promoting their latest album, Tranquility Base Hotel and Casino, but Timm 'wouldn't want to go back'.

"I miss them, and I do miss the job, because it's fun and I do miss visiting the odd exotic place. But I don't miss being away. That's why I stopped, because I've got a family and it was getting tough."

Timm lives with his wife Sam and their three children in Kiveton Park. He runs a photography business along with an arts company, Responsible Fishing, that makes temporary pieces from recycled materials.

The shift to Hillsborough was inevitable, he thinks.

"We were putting a lot of pressure on the city centre. We were having issues with overcrowding, and discussions with police about where the boundaries of responsibility lay. It was becoming almost like a beast. It gives us the opportunity to deliver a proper festival, which is what we've always strived to do, but you don't have to camp and it's within Sheffield. When we were doing multiple venues, some of the complaints we had were that you couldn't actually see the bands you wanted to."

And when the festival is in full swing and the bands are playing, how does he feel?

"Incredibly proud. Usually at the weekend I'll have a little moment at the side of the stage where I'll look out, and take it all in. It's usually on the Sunday night when everything's gone to plan. You look and go, 'We've done alright, actually'."

Tramlines 2018 happens from Friday to Sunday, July 20 to 22. Visit www.tramlines.org.uk for details and tickets.