A picturesque spot previously described by Manchester council as the highest point in the city has been found to be 8ft 6in lower than another nearby hill.

The Temple in Heaton Park was built in the 19th century and provides panoramic views of the city. A sign reads: “The Temple stands at the highest point in the City of Manchester.”

But analysis by the independent surveyors John Barnard and Graham Jackson found that the tallest point was in fact nearly 550 yards away in a wooded area next to a security fence and a communication tower.

Manchester council insisted the Temple remained “the highest and most significant viewing platform in Manchester”, but said it would update the signage to reflect the fact that it was not technically the highest point.

The 600-acre Heaton park was bought by the council in 1902 from the Earl of Wilton. It includes the grounds of Heaton Hall, a Grade I-listed neoclassical 18th-century house.

Viewpoint indicator at the Temple, now known to be the second highest point in Manchester. Photograph: Alamy

The council’s website states: “The ornamental Temple sits at the highest point in Manchester. It was designed in 1800 and we believe it was first used as an observatory by Sir Thomas Egerton, the first Earl of Wilton.”

Barnard and Jackson were called in when George Gradwell, from the Database of British and Irish Hills, noticed an anomaly at Heaton Park when looking at some data submitted by users.

“I thought it warranted further investigation,” Gradwell said. “I visited Heaton Park but it was not possible to tell visually if this alternative point was higher, since there is no direct line of sight between the two points. So I called in my colleagues at Graham and John from G&J Surveys to carry out an on-the-ground survey.”

They collected data using GNSS (global navigation and satellite system) technology, which measures heights using satellites. They found the temple was 353ft 4in high, while the other spot in the wood was 361ft 10in.

Barnard said: “A feature of the Temple is it’s claimed to be the highest point in the Manchester metropolitan district. There is a noticeboard next to the building asserting this.

“No doubt many people have stood within the Temple, admiring the views over Manchester and beyond, while at the same time feeling pleased that they are standing on the highest point in the district.

“Our data now shows a new highest point for Manchester has been found. The new summit position, in the wood next to a security fence, is clearly the highest point.

“In some ways, it is a pity because the Temple makes a much more impressive structure to crown the highest point and good views of the surrounding area can be obtained from there.

“But the good news is the new summit is only 547 yards away, and there is a pleasant walk between the two positions, so enthusiasts can take in the views.”

A Manchester city council spokesman said: “The Temple remains the highest and most significant viewing platform in Manchester. While not quite the highest point in Manchester, it is the best place to witness Heaton Park’s spectacular elevated views of the city and surrounding area. We will be updating our signs and information to reflect this.”