Planning restrictions on home and business extensions are to be eased by the government as part of a package of measures to help kick-start the economy.
The coalition wants to encourage tens of thousands of families and companies to expand their properties, giving a much-needed boost to economic activity.
Another 16,500 first-time buyers are also to receive help getting on the housing ladder under an extension of the FirstBuy scheme to be announced by the Prime Minister and Deputy Prime Minister.
The coalition is to help first-time buyers and encourage expansion
Would-be homeowners without a deposit are given an equity loan of up to 20% of the purchase price under the scheme.
The Prime Minister will say: "This government means business in delivering plans to help people, build new homes and kick-start the economy.
"We're determined to cut through the bureaucracy that holds us back.
"That starts with getting the planners off our backs.
"Getting behind the businesses that have the ambition to expand.
"And meeting the aspirations of families that want to buy or improve a home."
Homeowners and businesses will, for a limited time, be able to build much bigger extensions without planning permission than at present, under the changes to be unveiled today.
The new Permitted Development Rights will make it easier to install conservatories and loft extensions without going through weeks of planning bureaucracy and form-filling.
Full planning permission - required for extensions of more than a few metres from the rear wall of any home - will only now be needed for those beyond six or eight metres, depending on whether it is terraced or detached.
Businesses will be able to expand shops by 100 square metres and industrial units by 200 square metres.
Shops and offices will be allowed to develop up to the boundary of the premises.