THE size and appearance of a two-storey extension to a church would damage the church both aesthetically and architecturally, and any necessity for the extension was insufficient to justify that, Chancellor Mark Blackett-Ord ruled in the Consistory Court of Leicester diocese. He refused to grant a faculty for building works to All Saints', Cossington, a Grade II* church said to be of 12th-century origin.

The petition, brought by the Rector and churchwardens, sought permission for the construction of the extension on the north side of the church, to provide two large meeting rooms, a vestry office, plant room, kitchen, lavatory, stairs, and entrance lobby. At the request of the petitioners, the Chancellor did not hear oral argument, but dealt with the petition on paper.

A questionnaire that was circulated in the village of Cossington in 2003 described the scheme as "a proposal for a modest extension to the north of the building". By 2009, however, the plans proposed a much bigger extension, which was to be the same length as the nave, and would be on two floors, so that the apex of its roof would be higher than the highest point of the side aisles of the church, although not as high as the nave roof. The proposed access into the entrance lobby was given a small right-angled triangular porch roof, which would be prominent because it was intended to be the principal entrance to the church.

The Chancellor said that the shape and angles of the porch were at odds with the lines of the existing roof, and were "more suited to a community hall than an architecturally important church". The whole result of the plans was, he said, "a substantial building with a mixture of architectural details which relate[d] neither to each other nor to the church to which it was intended to be attached", and it was not the "modest extension" that had been suggested.

There were no formal objectors to the petition for the faculty, but the Society for the Protection of Ancient Buildings (SPAB) and English Heritage expressed their dislike of the proposed extension. The SPAB said that it was "disproportionate in scale to the existing church, and therefore damaging to the character and setting of a Grade II* listed church". English Heritage said that "the impact of this extension is so harmful" that a faculty should not be granted.

The Chancellor said that he did not know why a parish of about 450 persons required a church that needed a meeting room for 150, and a full-size classroom, as well as substantial seating in the church itself. If such a substantial structure was to be attached to a Grade II* listed church, then "an architectural design of the very highest quality" would be required.

The law was that the Chancellor had to consider (1) whether the petitioners had proved that there was a necessity for some or all of the proposed works, either because they were necessary for the pastoral well-being of the church, or for some other compelling reason; (2) whether some or all of the works would adversely affect the character of the church as a building of special architectural and historic interest; and (3) if the answer to (2) was "yes", then whether the necessity proved by the petitioners was such that the court should grant a faculty.

The Chancellor decided that the petitioners had not proved "a necessity" for an extension of the size proposed, and that, even if the extension was "necessary", the faculty should not be granted because the particular size and appearance of the extension would "damage the church in its churchyard setting both aesthetically and architecturally". The "necessity" was insufficient to justify that.

The proposed extension was likely to survive for centuries, the Chancellor said, and "we owe it to those who will worship in All Saints' in future centuries, as well as those who contributed to the building of the church in the past, that any extension . . . is of the highest aesthetic and architectural merit."

Petitioners should "treat seriously the opposition of English Heritage or the amenity societies", the Chancellor said. The court frequently disagreed with those bodies, but, where they expressed strong objection, "petitioners must realise that their scheme is at risk." The architect should have warned the petitioners that this scheme might fail, he said, and significant works to historic buildings required professionals who were experienced and specialist in that field.