The entire Swindon Transport Plan would be jeopardised if the park and ride at Junction 16 of the M4 is not allowed to go ahead.

This is the view of Swindon Council's principal planning officer, Rob Jones, the first witness to speak at the public inquiry into the development.

"Government guidance states that local authorities should carry out their land use policies and transport programmes to reduce growth in the length and number of motorised journeys, to encourage alternative means of travel which have less environmental impact and to reduce reliance on the private car," he said.

"A park and ride facility at Junction 16 is a key element in the Swindon Transport Plan. Without this park and ride the transport plan would be seriously, possibly fatally flawed."

The transport plan was published this year and covers the next decade. One of its main aims is to reduce congestion in town.

Mr Jones added that the fact that the proposed buffer site is in the rural buffer zone between Swindon and Wootton Bassett does not contravene planning laws.

He said: "A draft planning regulation advises that non-green belt locations can be considered as candidates for park and ride schemes. The appeal site is not a green belt."

Swindon Council applied for a nine-acre park and ride site at Spittleborough Farm 18 months ago, but was refused planning permission by North Wiltshire District Council.

The borough council lodged an appeal and the Government inquiry, which started yesterday under planning inspector Richard Hollox, is expected to last eight working days.

This week evidence will be heard from Swindon Council and its supporters, including Wiltshire County Council. Next week it will be the turn of North Wiltshire District Council and others who do not want the development.

This Friday will see James Gray, MP for North Wiltshire, speak against the park and ride he cannot speak next week because he will be at the House of Commons.

He said: "I will be appearing on behalf of the large number of local people who are against the proposal and have approached me for help.

"I am utterly against this for several reasons. Park and ride has not reduced congestion in other places such as Oxford; this one is on the wrong side of the motorway so drivers will have to double-back on themselves to get to it; and the fields between Wootton Bassett and Swindon are some of the most important fields anywhere. The corrosion of the rural buffer would be a step towards Wootton Bassett becoming part of Swindon."

The inquiry should finish on December 14. The inspector's decision is not expected until spring.

n Most of the sessions start at 9.30am and run all day, but an evening session has been organised on December 13 for members of the public who work during the day. It starts at 7pm in Wootton Bassett Rugby Club, Stoneover Lane.