David Cameron says he is "sorry" for all the "hard-working Conservative councillors" who lost their seats after a bruising night in the local elections.
Labour took control of a series of key councils at the expense of the Tories and Liberal Democrats.
Among the key councils taken by Labour are:
The Prime Minister was also embarrassed by losses in his Oxfordshire constituency. Labour took the seats of:
- Witney Central
- Witney East
- Chipping Norton
Labour leader Ed Miliband says he is determined to show that "we can deliver Britain the change it needs".
Deputy Prime Minister Nick Clegg says the local election results have left him "really sad".
Voters delivered a bruising verdict on the coalition government as Labour made big gains.
Speaking outside his home this morning Mr Clegg said he was "really sad" so many colleagues had lost their seats.
Labour leader Ed Miliband thanked the thank voters who backed his party and said he was determined to show that he could deliver Britain the change it needs.
George Galloway's Respect Party followed up its shock by-election victory by winning five seats on Bradford Council - including that of the Labour leader.
– George Galloway, Respect party
By anyone's calculation it's been a fantastic night for Respect. We took seats off all three of the mainstream parties. We took seats in Bradford West, my constituency, but also outside of Bradford West. And we took the head off the rotten fish that is the Bradford City Council. We defeated a council leader who sat there, apparently impregnable and utterly complacent, for a decade and a half or more."
With around half of votes counted:
- Labour has 470 new seats
- Set for overall gains of more than 700
- Tories likely to lose more than 350 seats
- Liberal Democrats set to lose around 200 seats
With counting still under way in London, Conservative Boris Johnson is establishing the kind of lead which could see him returned to to be London Mayor for a second term.
Election organiser London Elects was not releasing precise figures for ballot papers counted, but graphs on its website showed a clear early advantage.
Liberal Democrat Brian Paddick is trailing well behind the two front-runners, locked in a battle for third, fourth and fifth places with Green Jenny Jones and independent Siobhan Benita.