Environment officials are asking for access to thousands of ex-directory phone numbers so that they can alert people when their homes are in danger of being flooded.
However, following lapses in data security, with the government criticised over missing computer disks containing details on millions of child benefit claimants, there may be nervousness about allowing the Environment Agency access to numbers.
Nearly half of households with a landline in the UK now have an ex-directory number. The government's information commissioner, Richard Thomas, will make the decision whether to allow the agency, which is overseeing the UK's floods strategy, the right to have them.
Baroness Young, the agency's chief executive, said: 'Being able to communicate with people fast is really important when it comes to flooding. It may be serious enough to be talking about evacuation. Flash flooding can happen very quickly.'
More than 55,000 homes and businesses flooded last summer in the worst deluges since 1766. They caused huge disruption in Yorkshire, Gloucestershire and Herefordshire, with transport links, schools, power and water supplies hit. Thousands were left without drinking water and £3bn of damage was done.
No early-warning system was available for 35,000 homes. Although the agency has a flood warnings system, only 41 per cent of those eligible to receive the free service, because they live in an area with a high risk of flooding, have signed up for it.
A review into last summer's floods, carried out by Sir Michael Pitt, recommended that there had to be a better system for delivering flood warnings, despite the extra costs.
He called on the government to grant the Environment Agency access to its full electoral roll, including phone numbers.
