Defence secretary says in addition to helping victims, armed forces will also carry out a rapid assessment of damage caused

Communities struggling to cope with the consequences of winter storms could have been offered support from the armed services much earlier, the defence secretary has said.

Philip Hammond told the Andrew Marr Show on BBC1 that the armed forces could have arrived sooner, as he announced that another 5,000 troops were on standby. He also said Royal Engineers would be asked to compile a rapid assessment of the damage to Britain's infrastructure following weeks of high winds and torrential rain.

Hammond's acknowledgement that troops could have been deployed more quickly will be seized upon as further evidence of government failures in responding to the floods.

It is understood that the decision by the MoD to deploy troops is triggered by requests from government departments such as Eric Pickles' Department for Local Government or local authorities themselves - but few specific requests were forthcoming.

Large parts of Britain remain on high alert as people battle to protect their homes and communities from the floodwaters, which are still expected to rise in places despite a break in the storms.

The Environment Agency has 16 severe flood warnings in place for south-west England and the Thames Valley, as well as nearly 150 flood warnings and 230 flood alerts. Hammond said more than 3,000 troops were currently deployed and 5,000 more were available if needed.

"We've agreed with the Environment Agency that we will use Royal Engineers to do a very rapid inspection of all the nation's flood defences," he said. "So we're going to try and do in five weeks what would be about a two-year programme of inspection. This series of weather events over the past two months has caused some quite serious damage to our flood defences."

Hammond said the government's response to the crisis had been "proper", but that in future it would be likely to use troops earlier.

"We're dealing with an extraordinary set of weather events. It's taken some time to mobilise the resources that are necessary to respond," he said. "We offered troops quite a long while ago to civil authorities who wanted them. What we've done over the last 10 days is push them a bit more aggressively at those civil authorities.

"Putting military liaison officers into the gold commands so that they are embedded in the system has been a major step forward and I think probably we will want to make sure in future that we do that at a very early stage in any emerging problem."

Hammond added that ministers were planning to spend more on flood defences. "We're spending more in this four-year period than we did in the previous four-year period. We'll spend more again in the next four-year period," he said. "But of course there has to be a proper balance of costs and benefits drawn.

"Further targeted investment will mean that we become more and more resilient as events like this unfortunately probably will become more and more common."

The government has appeared flat-footed over its response to the floods, which claimed two lives on Friday – James Swinstead, an elderly passenger on a cruise ship in the English Channel, and Julie Sillitoe, 49, a minicab driver whose car was hit by falling masonry in central London.

In an interview with the Observer, Ed Miliband questioned why many Conservatives, including David Cameron, had appeared to backtrack on climate change rather than saying that it was a cause of the current weather-related problems.

Asked to respond to Miliband's comments, Hammond said: "Climate change is clearly happening. It is clearly a factor in the weather patterns that we are seeing. That's why we are investing significant amounts of money in increasing our flood resilience in the UK.

"Of course these floods are a terrible tragedy for all the people involved, but we should not forget that hundreds of thousands of people have been protected from flooding by the investment we have made over recent years."

A ComRes poll for the Independent on Sunday found that six out of 10 voters thought the government had failed to get a grip on the flooding crisis.

Both Cameron and Miliband have altered their travels plans so that they will remain in Britain this week.