Siobhan Donovan has made a surprise return to The Archers with actress Caroline Lennon reprising the role after 13 years.

Thursday’s episode of the BBC Radio 4 series saw her son Ruairi, voiced by Arthur Hughes, receive a surprise message from his late mother during his 18th birthday celebrations.

In a message recorded to CD, she told him: “I desperately want you to know how fiercely I loved you – love you – and I’m so sorry I’m not there.”

Siobhan recorded the message when Ruairi was four years old as she fought terminal cancer and ensured it was hidden until he turned 18.

A controversial character for many listeners, Siobhan exited the drama in 2007, leaving Ruairi in the care of his father Brian Aldridge.

Brian’s wife Jennifer was faced with accepting the child of her husband’s affair into their family. However, she keeps Ruairi company while he listens to Siobhan’s message.

Recording for the episode marked Lennon’s first scene for The Archers in more than 13 years.

Jeremy Howe, editor of The Archers, said: “Possibly only The Archers would resolve a story after 18 years – yes, 18 years – and with such a touching scene.”

The Archers continues on Monday November 16 at 7pm on BBC Radio 4 and BBC Sounds.