As we saw in last night’s episode of EastEnders, Cora Cross has been keeping a massive secret for near on five decades: her daughter Ava, who the rest of her family believes was stillborn, was actually given up for adoption. 

As Cora marked Ava’s 48^th birthday, she confided this news in her close friend Patrick. So why has Cora stayed silent for so long? 

“It’s partly an enormous sense of guilt, a sense of privacy, and to keep things as safe and uncomplicated as they could be,” says actress Ann Mitchell, who has played Cora since 2011. “She was 18, unmarried and, at that time in social history, that was a very big stigma.” 

So has she ever thought about trying to find Ava herself? 

“No. She might have thought about it, fantasised about it, but it was never reality for her. It would have been too upsetting for her husband and for the rest of the family to introduce another child into the mix. It has been a huge burden in a sense.” 

It isn’t long though before Tanya learns about Ava’s existence from Patrick and sets about tracking down her long-lost sister. Next week, we’ll see Tanya trace Ava to a school where the woman works. But, after meeting her in the flesh, Tanya decides not to reveal the truth about their family connection. 

The trouble is that Tanya accidentally leaves her purse at the school and soon enough Ava (Clare Perkins) is knocking on the Brannings’ door with the aim of returning the missing item. 

“A pleasant young woman turns up at the door saying that she’s returning Tanya's purse, which is an incredibly kind thing to do in this day and age. And Cora’s delighted – she invites her in for a cup of tea, as you would. 

“Cora thinks Tanya has decided to put Oscar into a new school that’s a long way from where they live and she's very cross because she thinks there should have been a family conference about it. 

“When Tanya shows up, Cora says that she wouldn’t have known anything about this if it hadn’t been for this good Samaritan. And then Cora says, ‘I’m sorry. I didn’t get your name?’ and the woman says ‘Ava, Ava Hartman.’ And that’s the name of the child that Cora gave away – the nurse at the time told her what the child’s name would be.”

So how does Cora feel about what Tanya and Patrick have done? 

“Utter shock. She’s completely traumatized by it, both by the event and also by the betrayal by Tanya,” admits Mitchell. “It also took a huge amount of trust to tell Patrick and for him to have betrayed her is incomprehensible. She tells him to never darken her door again.” 

Of course, this being EastEnders, the implications of this revelation will be enormous, especially in the run-up to Christmas: 

“Christmas is going to be huge. It is going to be mayhem. It was always my intention that Cora would become more complicated and interesting than she was when she came in. So the whole image of her has changed, which is partly to do with her job at the charity shop, but also because of the necessity of women of my age to reflect the interests of the audience. I’m thrilled to bits with the storyline.”