Russell T Davies is predicting that Doctor Who could lose up to 1.5m viewers when it returns in a new 6.20pm slot next month.

The writer and executive producer of the series told the Broadcast television drama conference today that the BBC should maintain the later 7pm-7.15pm slot and the budget for the sci-fi series but it had mucked it up.

The BBC believes the programme would do as well in the new slot, he said. "Well, we'll see, but I think I'm right."

Not all time travel is welcome

He also said he would resist any move to film the series in HD - it would be too expensive and it was 'rubbish' to think no one would watch unless it was in high definition.

He said it had always been the plan to rest Doctor Who in 2009. He said he would use the time off to work on new projects, for instance for a 9pm slot with more adult, emotional content although nothing had been commissioned.

BBC Ariel

The Doctor and Donna travel back into ancient history, in the second episode of Russell T Davies's Bafta Award-winning time-travelling drama. When they arrive in 79AD, however, they discover psychic powers and beasts of stone running riot in the streets of old Pompeii. The time-travellers face their greatest challenge yet – can established history be changed, or must the Doctor let everyone die?