Researchers have discovered that Britain's highest mountain isn't in Britain. A recent cartographic survey by the British Antarctic Survey (BAS) has found that Mount Hope, at an elevation of 3,239 m (10,654 ft) above sea level, is not only the highest mountain in the British Antarctic Territory (BAT), but in any British territory. The survey, which incorporates new satellite data shows that Mount Hope is 337 m (1,106 ft) taller than previously thought, making it 55 m (180 ft) higher than Mount Jackson, the now second highest in the territory at 3,184 m (10,444 ft).

Large wedges of the frozen continent are claimed by Argentina, Australia, Chile, France, New Zealand, Norway, and the United Kingdom as sovereign territories. Britain's claim to the BAT goes back to letters of patent issued in 1908 and 1917 and extends in a triangle from the South Pole to 60° South latitude and spreading between 20° West and 80° West longitude. Though it covers an area of 1,709,400 km² (660,000 mi²), you don't hear much about it because under the 1961 Antarctic Treaty, Britain, along with the other countries, has suspended its claims indefinitely.

Over the past century, a concerted effort has been made to accurately map the BAT, but it turns out that previous mapping efforts done from the ground on overland surveys have left much to be desired. Because an accurate picture of the terrain is important for air traffic safety as well as pure science, BAS has been using new high-resolution satellite measurements accurate to within five meters (16 ft) to create more up to date topographical maps.

The new measurements show that not only is Mount Hope the tallest mountain in the BAT, it is the tallest of any mountain in any British Overseas Territory or the British Isles. By comparison, the tallest mountain in mainland Britain, Ben Nevis, is only 1,344.5 m (4,411 ft) above sea level. However, Mount Hope is not the tallest in the whole of Antarctica. That honor goes to Mount Vinson, which tops out at 4,892 m (16,050 ft).

"This is an exciting discovery within the British Antarctic Territory," says Adrian Fox, Head of Mapping and Geographic Information at BAS. "Modern satellite data highlights how inaccurate previous surveys and maps were for some parts of the region. As well as discovering Mount Hope is the highest mountain in the territory, we have identified several other interesting discoveries. These include new mountain heights, ranges in new locations by up to five kilometers and even some new peaks which hadn't been surveyed before.

"Maps with reliable measurements of the highest peaks are an essential safety requirement for flight planning. Accurate elevation data from satellite imagery now allows us to produce these resources for Antarctica, where flying is difficult at the best of times."

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