MIG wrote:

Not just conservatives; don't forget that a lot of the Left would no
sooner vote New Labour than Tory, lest their hands wither and fall
off. But one can't be sure if he had the resources to run and win as
an independent in 2004 without the New Labour machinery. And he
wouldn't just have to leave the party again, he would also have to
have yet another dramatic change of politics (as he did when he
rejoined) to convince people.

I think Labour would have certainly lost in 2004. They did actually select a
candidate before Ken returned. But hardly anyone had heard of Nicky Gavron
and she was routinely polling in fourth place and would have found it hard
to present herself as the credible anti-Livingstone alternative, even
amongst voters who didn't want the Conservatives as Simon Hughes had a
bigger profile. Labour were also still suffering a backlash over the war. So
I doubt Labour would have won without Ken.

One thing often forgotten is that the 2004 election was the *only* time the
London-wide local government (on whichever boundaries) was won by the same
party in power at Westminster since 1949. (And IIRC even in 2004 the
Assembly wasn't won by Labour.) And whilst the London County Council didn't
have such an exact match it's notable that it began with an 18 year Liberal
rule (I think in local government they used the "Progressive" label) from
1889-1907, which broadly corresponded to 20 odd years Conservative/Unionist
domination at Westminster (1886-1906), then 26 years under the Conservatives
(I think the local label was "Municipal Reform Society") from 1907 to 1933,
which was a period in which the Conservatives nationally were generally
weak, then Labour (under that label) from 1933 to 1965, again at a time when
they were nationally weak. The trend for London voters to want the
County/City Hall to be run by a different party from Whitehall is one of the
main constant features of London government, along with argument over
whether London is one community or several and conflict between boroughs,
whether east/west or inner/outer that is often reflected in different party
support levels.