Liberal Democrats put flood spending into sharp focus with a call to up spending by £500m – a move backed by flooding minister Dan Rogerson, who admitted there was a 'need to do better' on future protection schemes.

Tidal surges in Norfolk and Suffolk, and severe flooding elsewhere in the country over the winter, was highlighted by activists who warned of more to come, and called for Environment Agency recommendations for an extra £20m a year between 2010 and 2035, to be heeded.

The government has faced criticism for cutting flood defence spending, but Defra says spending has gone up compared to the last Parliament.

The parliamentary candidate for Somerton and Frome David Rendel, also attacked Conservative 'right-wingers' who he said would force a Conservative government to 'refuse to spend any money' on mitigating climate change.

The annual cost of flooding is thought to be around £1.1bn and could rise to £27bn by 2080.

In summarising the debate in the main hall in Glasgow yesterday, Mr Rogerson, cited the east coast tidal surge in December, and said flooding had a 'devastating' effect that was 'personal, social and economic'.

He told delegates: 'The motion sets out our determination to go further and work harder on tackling flooding. I would like to reassure people we take on board the need to do better.'

Activists also voted to make a sweeping raft of measures, including more research into natural flood defences such as peatlands, woodlands and natural coastal habitats, party policy.

It comes ahead of energy secretary Ed Davey's speech today where he will announce that householders in England and Wales are to be offered an additional £100m to fund energy-saving home improvements, after a government scheme proved so popular it ran out of cash within three months.

Appliciations for the first tranche of grants under the £450m Green Deal – intended to help fund items such as wall insulation, double-glazing and new boilers – opened in May, but the first year's money was all scooped up by the end of July, leaving a gap of several months before would-be home improvers could make fresh bids.

Aides said the new cash would help fill that gap and would remain on offer until it has all been spent.

Mr Davey is expected to tell the Glasgow conference that Lib Dems have delivered 'dramatic reform' in the energy market by being 'outsiders' and taking on vested interests.

He will announce that all of the major energy firms are now on schedule to meet the challenge he set last year to halve from five to two-and-a-half weeks the time it takes to switch between suppliers.

Yesterday's conference was dominated by business secretary Vince Cable's speech, in which he delivered an attack on 'lying' Tories who suggest the government can balance its books without raising taxes.

Dismissing his erstwhile coalition partners as 'Ukip without the beer', the business secretary said they were 'ideologically' committed to destroying public services and the welfare state.

He also called for more government borrowing to invest in major housing and infrastructure projects.

The intervention, came as the party fights to differentiate itself ahead of the general election.

Should flood defence spending be increased? Write (giving your full contact details) to: The Letters Editor, EDP, Prospect House, Rouen Road, Norwich NR1 1RE or email EDPLetters@archant.co.uk