More than 10million viewers are expected for tonight's finale of the latest Dr Who series amid anguished debate over whether David Tennant's Time Lord will be killed off.

Last week's cliffhanger saw his character beginning to regenerate, which happens every time a new Doctor Who is introduced.

The plot line for tonight's episode has remained such a closely guarded secret that the BBC has banned any preview tapes.

Fever pitch: Ten million fans are set to tune into Dr Who's finale on Saturday

The uncertainty over the fate of the character has sparked a rash of weird and wonderful predictions among the show's fans.

There are numerous conspiracy theories, including the suggestion that the entire current series will be shown to be 'not real' .

Some are predicting that Tennant will be replaced by the first Time Lady, with current sidekick Donna, played by Catherine Tate, being tipped. Enlarge 

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Other seasoned fans believe she will be killed off in tonight's show, following last week's action which saw the Doctor shot by a Dalek.

There is also a well- supported and widely-rumoured theory that rather than being replaced, Tennant will regenerate into two doctors, both played by him.

Adding to the confusion is the previously stated fact that the current Doctor Who star will appear in at least four more specials.

Such is the speculation amongst fans that some have claimed that announcement was all a big 'hoax' to hide the fact that he is leaving tonight.

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Others have suggested that the four specials, taking place before the next full series of the show in 2010, will pre-date the character's death.

Many believe that even if Tennant does not go tonight, he is unlikely to return for the full series in two years.

Among those being tipped to replace him are the bookmakers' favourite Robert Carlyle as well as Jason Statham and Alan Davies.

Other names in the frame are believed to be Simon Pegg and Cold Feet star James Nesbitt.

Some fans fear that the BBC has been using the suggestion of a new Time Lord as a cheap ratings ploy.

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On the show's many associated fan websites there is widespread criticism that this is just a ' windup'.

An avid viewer said it would be a 'dreadful trick' to promise this most 'dramatic turn of events' and then for it not to happen.

One said: 'The fact that they are using regeneration as a cliff-hanger gimmick here, would suggest to me that he isn't going anywhere for some considerable time to come.'

Another added: 'Of course it's a ploy. A ploy to get people to watch the last episode, that's why if a regeneration doesn't happen it seems like a cheap nasty cop-out and there is no need to do it.'

One cynical fan said: 'It's a windup. No way would they let David Tennant go without some decent parting words.'