A complex legal battle over plans to build 2,000 new homes near BT’s Adastral Park has continued into extra time.

The case, which began on Thursday and was originally scheduled to be heard over two days, is looking at Suffolk Coastal District Council’s blueprint for future growth.

The original time estimate has now doubled and today campaign group No Adastral New Town (NANT), which brought the High Court challenge, wrapped up their evidence.

Its lawyer, Richard Buxton, reiterated to judge Mrs Justice Patterson that Suffolk Coastal failed in its legal obligations when it approved the Core Strategy of its Local Development Framework, which sets out how the district will grow over the next 20 or so years and allocated the site near the River Deben for the extensive development.

Arguing that there were “fundamental problems” in the way the council handled the lengthy process, he said: “Crucially inaccurate information in the environmental material plainly influenced the way the public were consulted and the committee were informed.”

Claiming that the authority dealt with the five preferred options for housing allocation “without an apparent knowledge of the River Deben or certainly its special protection area status” he added: “Here they got down the line by making an essential mistake and not revisiting it, then continuing down the line for a long time until we are in court today.”

However, Paul Chadarevyan, for Suffolk Coastal, augmented his written submissions to the court, which were reported on Friday, by outlining to the judge the highly complicated process a council must go through in arriving at a Local Plan or Core Strategy.

He said the authority was preparing “a Local Plan of considerable complexity”, bearing in mind the number of local protected sites, the housing pressures of the Ipswich area and the need to make provision for Suffolk Coastal’s own needs, and that this placed upon it a “considerable burden”.

He continued: “The information which is obtained is sieved and considered and rationalised internally by the members and officers actively trying to bring structure to a process which begins in a rather nebulous fashion.”

In his written submissions he argued that council members had been well aware of the issues surrounding the Deben Estuary and that the authority had lawfully adopted its Core Strategy in compliance with the requirements of the Strategic Environmental Assessment Directive and Regulations and the Habitats Directive and Regulations in the process.

The hearing continues. When it ends the judge is expected to reserve her decision and to give a written ruling later this year.