ALTERATIONS to Junction 16 of the M4, needed to cater for the Wichelstowe development, could become an accident blackspot, environmental campaigners argued in court yesterday.

The Wiltshire Branch of the Campaign to Protect Rural England say they have no objection to the development of 4,500 new homes at Wichelstowe, a project for which planning consent was granted by Swindon Borough Council as long ago as 2005.

But, in order to meet the access needs of the “Front Garden” development, radical changes will have to made to the Junction 16 interchange, including a tunnel under the motorway linking up to Hay Lane, the branch’s solicitor, Richard Buxton, told a top judge yesterday.

At London’s Civil Appeal Court, Mr Buxton argued that, under current proposals, the width of lanes at the interchange and the “right hand cross-over” do not meet safety guidelines and would result in a real risk of collisions and danger to the public.

But these concerns were not echoed by Lord Justice Pill who dismissed the case.

When planning permission was granted for the housing development five years ago, it was subject to no less than 102 conditions, but Mr Buxton focused on “Condition 99” which related to the safety of the access route from the M4.

The condition stated that none of the new homes could be occupied until it was complied with but, in April 2008, the Borough Council “discharged” it at the request of developers, Taylor Wimpey, and with the approval of the Highways Agency.

Describing the safety issue as “fundamental”, Mr Buxton argued that it was wrong to do away with Condition 99 whilst the interchange was “not established as safe”. He also criticised the council for saying that safety issues could be fully addressed in a “two-stage process” and could be left over for consideration at “the design stage”.

However, dismissing the judicial review challenge yesterday, Lord Justice Pill said he could detect no legal flaw in the Borough Council’s stance - which it said was based on expert advice - and the Wiltshire Branch’s appeal had “no reasonable prospect” of success.