This has always been one of my favourite "What-Ifs".
Callaghan was to admit later on that he had made a massive error in judgement in not going for a October 1978 election.
I agree that he would have won with a majority of around 20 seats.
Callaghan also said he would have had resigned the Premiership mind may through that Parliament. He favoured Dennis Healey(as he did in the real life Labour leadership election of 1981), Healey would have been leader but I wonder what would have happended if Micheal Foot had won any Leadership election if this timeline and become Prime-Minister. What a scary thought!!!
Michael Foot wouldnt have been a bad prime Minister. He was character assasinated by the right wing press. Though I would have prefered Healey.
If Healey wins any election to suceed Callaghan, then I agree with the idea that it would keep the right wing of the Labour Party, so there would been no SDP breakaway, it would only happen with Foot becomes Prime-Minister.
If the Falkland war happens as per our history in April 1982 then if Healey was prime-Minister he would not have fought, but starngley Foot(who backed Thatcher in 1982) would and attempted to retake them.
As for the Conservatives Thatcher would have been out by Christmas either by her own hand or by a forced Leadership vote. Jim Prior, Howe, Hezzez, and Peter Walker would have gone for the Leadership.
This very idea of a 1978 election formed the basis of a 1993 TV programme on BBC2, with interviews with Healey, Callagahan etc, and TV news broadcasts from this world, it was quite good, and as far as I know has never been repeated.