Why is Tosh leaving Shetland? Alison O'Donnell's answer comes down to one word

Shetland, the BBC One crime drama based on Ann Cleeves' novels, has been on the air since 2013, and O'Donnell has been in it from the very first episode. She plays Alison "Tosh" McIntosh, who started out as a detective sergeant beside Douglas Henshall's DI Jimmy Perez and worked her way up to detective inspector. On June 12, 2026, she announced that series 11 would be her last. The six episodes premiere Thursday, November 12, at 9 p.m. on BBC One and BBC iPlayer. In the US, BritBox carries the first ten seasons and has confirmed Shetland will return in 2027.

What she said when she announced it

O'Donnell is 43 now. She was around 30 when she got the part, which is why her goodbye statement reads less like an actor leaving a job and more like someone leaving home.

"Playing Tosh has been the greatest gift an actor could hope for," O'Donnell said.

"I grew up in this job," she added. "It has shaped me as an actor, and as a collaborator."

The actual reason

Asked to explain the decision as series 11 approached, O'Donnell said it was "not down to one particular thing" but "a coming together of various components." The biggest of those components sounds like simple arithmetic after 11 series: "at this point it feels like we've probably explored it enough."

She also said there would never have been a moment to step away that "didn't feel sad and bittersweet." So she stopped waiting for one.

"Something in me said 'leap', and so I did."

The last time someone left

O'Donnell has been on the other side of this. Henshall left after series 7 in 2022, and she said she was "honestly bereft." Ashley Jensen took over the lead as DI Ruth Calder from series 8, and over four series Calder and Tosh became a real partnership. Now it's Jensen's turn to lose a partner.

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"Tosh is such a stalwart of that incident room," Jensen said. "She leaves an enormous hole."

How Tosh goes

The BBC hasn't said, and O'Donnell isn't telling. Series 11 opens with a car pulled out of the sea with the skeletal remains of an unidentified man in the trunk. The car belongs to Dr. Raymond Linden, a respected local doctor who left the island nine years earlier, and Calder and Tosh have to work out what happened to him while the people around him tell conflicting stories. Gregor Fisher joins the cast as Donald Pierce, a lonely recluse who gets pulled into the case.

"These were some of the most challenging scenes I've ever shot for the show," O'Donnell said.

"It's all in there," she added. "I think it's a memorable exit. We'll see!"

The crew already had their own send-off planned. On O'Donnell's last day of filming, a lot of them came to set dressed as Tosh, "wearing fair isle jumpers" with "their hair up in a bun."

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