The government's plans to introduce a "new presumption in favour of sustainable development" could have the effect of undermining the sustainability of local high streets, retailers have warned.

The Chancellor announced in the Budget that the default answer to applications for new development would be "yes" and that planning bodies must prioritise jobs and growth. A number of measures to streamline planning applications were also announced, including a 12-month guarantee for the process of all applications, including appeals.

Jonathan James, who owns six stores in Cambridgeshire, said the government was "so hell-bent on growth that I hope they're not lulled by major multiples at the expense of the high street."

Association of Convenience Stores chief executive James Lowman said: "Radical changes to planning must not override the ability of councils to plan for sustainable high streets."

However, the Budget announcements that corporation tax would fall 2% this year to 26%, and an agreement by banks to increase the availability of credit to small businesses by 15% were welcomed by small traders. The Chancellor also announced the creation of 21 Local Enterprise Zones to drive growth.