The authority already applies the target to schemes of more than 14 homes, but wants to extend it to cover all residential projects.
Affordable targets have been scrutinised since Blyth Valley Borough Council's 30 per cent requirement was quashed by the High Court after a challenge by house builders (Planning, 30 May 2008, p4).
Barratt Homes challenged similar policies in Wakefield Council's core strategy (Planning, 26 June, p2). "Local authorities need to ensure that there is sound evidence to justify their figures," stressed Barratt's adviser Peter Village QC of 4-5 Gray's Inn Square.
Bournemouth's policy has been judged sound by the Planning Inspectorate. But experts have questioned the viability testing, which is based on 2007 house prices.
Drivers Jonas partner Steve Billington maintained: "Our studies have assessed project viability at two points in the market to see how the policy works in different conditions. If Bournemouth has not tested the policy in conditions that are considerably worse, then it might not work."
The council's principal planning officer Alan Cheesman said: "If it can be shown that a scheme cannot provide affordable housing then we won't take any. It should not affect the number of schemes coming forward."