Writer Peter Harness has talked a little about his upcoming two-parter for Series 9 and promised a big cliffhanger.

Speaking to Digital Spy he said: “It’s a bit unbelievable to be bringing [the Zygons] back again – and also Osgood as well, another fan favourite.”

He adds: “It’s a privilege to be telling a story about those two, and I think it’s quite an exciting story as well. Unfortunately I’ve got two fan favourites in my hands now, which can only set me up to disappoint people!”

He concludes: “I tried to do the biggest cliffhanger I possibly could.”