Come the general election, the group – whose ranks have now swollen to 33 councillors – will be concentrating on Hull North, held by Labour's Diana Johnson.

Council leader Carl Minns said: "I think there will be a very close election in Hull North, it's a target national seat for the party. I have been canvassing in Hull for 11 years now and there were times when I would go out canvassing and there was not one single person who would vote Labour. I think nationally they are collapsing."

But Labour group leader Steve Brady said they could "dream on" – and when it came to a general election they would end up being squeezed between traditional Labour voters and the Tories.

He added: "Labour voters will be very, very uneasy about switching votes because they know Labour has delivered substantial gains to people in Hull, like family credits. I think the Tory vote will squeeze the Lib Dem vote and they will probably end up third."

His sister, Coun Mary Glew, who increased her majority in Southcoates West, warmed to the same theme in her own victory speech.

She said: "I feel this is a Labour city, it was always a Labour city at heart and I am sure it will continue to be one."

Lib Dem leader Nick Clegg, however, was in no doubts about the shape his party is in when he came to Hull yesterday to congratulate his troops.

There was a spring in his step as he emerged from the back seat of a car onto the steps of the Guildhall, where he shared a warm handshake with Coun Minns before posing for photographs with councillors.

He said Lib Dem victories showed the party had wrenched power from Labour in its northern heartlands.

He said: "Overnight we have broken Labour's grip on the North and we are now the new broom in great cities like Hull."

He added: "We are going to carry on doing the work we are doing so well in Hull, which is listening to people and working hard to keep council tax rises low. We have done phenomenal work here to keep crime rates down and that's what we must do; tackle anti-social behaviour to make the city safer and continue to deliver value for money."

Making a reappearance on the Labour benches is controversial former council leader Colin Inglis, who signalled his return to politics, following his suspension from Labour and a battle with stomach cancer, with a typically robust challenge.

He said he had thought "long and hard" about returning to politics, but "having kept a weather eye on the place while I was ill and particularly over the last two or three months what struck me was the triumph of style over substance. There is complete vacuousness where politics is concerned."

The Lib Dems, who took two Labour seats and those of three former Lib-Dems turned Independents, managed nearly 42 per cent of the vote against Labour's 34 per cent. The Tories took 14 cent – with the Independents at five per cent. Turnouts were shockingly low. Thirty-six per cent was the highest achieved in Bricknell ward, against just 17 per cent in Orchard Park.