First look: Downton Abbey episode eight - Lady Rose vows to rebel and marry Jack Ross

Lady Mary confronts Lady Rose about her relationship with the jazz singer

A defiant Lady Rose vows to marry Jack Ross in Downton Abbey (ITV)

Following Ofcom’s decision not to investigate the rape scene of episode three, there is yet more controversy to come in Downton Abbey.

In the teaser trailer for episode eight, the final show of the series bar a promised Christmas Special, Lady Mary ushers Lady Rose into her room to reveal that she knows about her illicit romance with black American jazz singer Jack.

Mary asks Rose why she is going to bed early, to which she responds, “I've had rather a tiring day”.

Taking her cue, Mary confronts Rose, explaining in a firm but motherly tone, “My dear, all I want is for you not to lose control of your life”.

The Countess of Grantham’s great niece looks visibly shocked that her secret is out, but stoically shows no shame, arguing, “I love him, and I won’t listen to any imperialist nonsense about racial purity and how he should be horse-whipped for daring to dream.”

Despite her cousin’s protest, the feisty Rose continues on the defensive.

"I’m going to marry him Mary and I don’t care what it costs and I won’t keep it a secret, not once I’ve told Mummy,” she says defiantly.

“I want to see her face crumble when she finds out.”

Downton Abbey continues on Sunday at 9pm on ITV