"You don't look like no Doctor to me, love!"

What with all the camp shouting, garish costumes, grotesque gurning and the feeling that you're watching the same thing over and over again every three minutes, the Eurovision Song Contest will prove more than an adequate replacement for Dr Who this week.

Meanwhile the present hiatus in the time wizard's jabbering perambulations around the galaxy affords an opportunity to speculate not just on when the good Doctor will get round to actually placing himself in a decent story again, but also just who, by way of surprise loud-voiced variety-esque guest stars, Russell T Davies might have lined up for a cameo before the final episode and the usual plot about how the world's in danger of being destroyed for the 75th time.

At this stage last year there were still the delights of Huw Edwards and Barbara Windsor to come; the year before, Anne Robinson's voice and Victor Meldrew. Based on a combination of painstaking research, detailed analysis, and looking at a few random pictures, all, none or fewer of the following five personalities have emerged as the most likely candidates this series:

1) JESSIE WALLACE
Playing a rough diamond living it up in Cardiff, her no-nonsense, tell-it-like-it-is attitude, coupled with a heart of gold, helps the Doctor mend a hole in the Rift that accidentally opens up when he shouts in a particularly echoing subway.

2) KEN DODD
Reprising his role of the Tollmaster from the 1980s story Delta and the Bannerman, Doddy joins the TARDIS crew for yet another whimsical pantomime episode set on a far flung planet peopled by bug-eyed monsters, bits of poorly CGI'd Cardiff and gay music.

3) NICK ROBINSON
There is a political crisis in the UK of the near-future. The Prime Minister, Tommy Blear, having held office for 10 years, is stepping down prematurely after a controversial foriegn policy initiative. His long-tipped replacement, Gideon Brone, suddenly goes AWOL. Has he been abducted by the leader of the opposition, an alien imposter named Daffyd Cameroon who claims to be from Cardiff but has actually come through the Rift? Maybe the BBC's political editor can help.

4) CAROLINE QUENTIN
Starring as the Brigadier: bluff, sassy, but trying to juggle a career with being a mother of two kids - one of whom is a stroppy teenager, the other a deaf mute - plus an estranged husband who works full-time for the Countryside Alliance.

5) RICKY GERVAIS
Martha walks into a room only to hear someone making a joke about black people. Her initial discomfort is quickly erased, however, when she realises the voice belongs to none other than funnyman Ricky Gervais, who is in the middle of another sell-out national tour. Gervais later wins the Doctor's favour after completely disarming Derek Jacobi/John Simm/whoever else ends up playing the Master with a remark about how all disabled people are tax-dodging frauds, which he delivers at the same time as someone in a wheelchair comes in the room.