She made her first screen appearance during episode 1796, originally broadcast on 12 June 2006 and was introduced by producer Bryan Kirkwood as part of the McQueen family.

One of her early stories introduces Niall Rafferty (Barry Sloane), Myra's abandoned son who returns for revenge on his mother.

The story concludes in a stunt when Niall explodes a church, killing Myra's daughter Tina Reilly (Leah Hackett).

Writers created a love interest for Myra in the form of Diego Salvador Martinez Hernandez De La Cruz (Juan Pablo Yepez).

In 2016, producers explored the character's backstory through the introduction of Sally St. Claire (Annie Wallace), a trans woman who fathered Myra's son, John Paul McQueen (James Sutton), before her transition.

This formidable matriarch of the village's most fearsome tribe keeps her troublesome brood in line with a mixture of love, understanding and bacon sarnies – all three of which have been in great demand during the McQueens dramatic tenure [...] Fiercely protective of her family, Myra's often has to choose between them.

[9] Executive producer Bryan Kirkwood announced that a "tall stranger", Niall Rafferty (Barry Sloane), would soon join the serial and "the McQueen family take him into their bosom – Myra's to be precise".

[8] Barber-Lane told Kris Green of entertainment website Digital Spy that Myra no longer wants to look for her son as "she thinks that she's a bad omen.

Barber-Lane told Daniel Kilkelly of Digital Spy that Myra believes Riley will benefit the McQueen family financially and take them out of the poverty they are in.

[19] A show spokesperson declined to discuss the contracts of Barber-Lane and Porter, but commented, "Theresa and her aunt Myra do come and go from Hollyoaks village".

Kirkwood contacted Barber-Lane and asked her to return from her break, explaining that he wanted Myra to become involved in "some quite heavy and serious material as well as the comedy", something which appealed to the actress.

[21] Kirkwood told an Inside Soap reporter that Myra would "sprinkle her magic dust on the McQueens and bring that unique warmth and comedy to the show again".

"[21] In 2015, the story team created a love interest for Myra in the form of Diego Salvador Martinez Hernandez De La Cruz (Juan Pablo Yepez).

Kirkwood used Myra and Diego's relationship to create some fun and light in the show, counterbalancing the ongoing darker stories with the rest of the family.

Barber-Lane explained that Myra fears that Diego will not be interested in her anymore because in Spain, "she's living that fantasy out and she doesn't want that to come crashing down".

Her claim is further supported when Diego spots the pair acting intimately and then witnesses Nathan showing Myra the lingerie he has bought for his girlfriend, Rachel Hardy (Jennifer Brooke).

[30] The casting team hired Jacey Sallés to play Diego's millionaire mother Juanita Salvador Martinez Hernandez De La Cruz in September 2016.

Having tried to con Frankie Osborne (Helen Pearson), Diego makes plans to move to Spain with Myra and their daughter Carmina.

[28] Writers ended the feuding between Myra and Sally after John Paul is involved in a car accident and temporarily loses his vision.

When Mercedes becomes engaged to footballer Riley she immediately takes a liking to his rich background, to the dismay of his mother Heidi Costello (Kim Tiddy) who Myra feuds with over the wedding.

Mercedes' ex-lover Dr. Paul Browning (Joseph Thompson) returns following being released from prison, found innocent of the murder of Lynsey Nolan (Karen Hassan), and reunites with her, later getting engaged.

Myra decides she wants to sue the hospital, so that she might pay back her loan, but Jim McGinn (Dan Tetsell) later tells her that it is not a case worth pursuing.

She was presumed dead, until John Paul follows Jim to the airport, where it was revealed she was wearing a bullet proof vest and is alive, however, she must flee so Doctor Browning will be locked away for the crime.

Myra, Phoebe and Mercedes manage to convince Carmel against the idea, but when they go to pay their respects to Sonny at the lake, they look on in horror as the police are pulling the car out of the water.

Myra then helps Carmel to get Phoebe's mobile phone to the police which holds a confession that Sonny had said to the McQueen's in order to free Theresa from prison.

Sonny sneaks aboard the train and attacks Phoebe and Theresa, before Sienna Blake's (Anna Passey) car on the tracks causes it to derail.

The day after her return, a young Venezuelan man named Diego Salvador Martinez Hernandez De La Cruz (Juan Pablo Yepez) arrives in Hollyoaks searching for the "Countess of Chester".

In March 2016, Myra is furious to learn that John Paul's transgender boss, Sally St. Claire (Annie Wallace), has sacked him, so behind his back she confronts her.

Myra later gives birth to a girl called Carmina Celeste, named after her late daughters Tina and Carmel and her niece Celine, who was recently murdered.

[64] Rianne Houghton, also from Digital Spy, hoped that Myra and Sally's relationship would be successful, commenting, "Please let this be a happy ending, Hollyoaks!