George Brown would be drunk all the time!!!! But it would be funny!!!!
Roy Jenkins either as Labour Leader after Wilson retires in 1972 after a 1970 victory. Wilson was sent on retiring then, and Jenkins would have been the clear front-runner. Or you could have him with the SDP in 1983 or 84 if the Falklands goes wrong.
Ian Macleod's death just a month after the 1970 victory when he was Chancellor doomed Heath, many think that with Macleod alive Heath would not have made many of the mistakes he did in 1972,73. Heath wins re-election in 1975, and retires say 1977, 78 Macleod wins the leadership election, he would only be 62 or 63.