RESIDENTS in the west of the district were left scratching their heads last week, after a series of orange flashes lit up the sky.

The flashes caused much speculation on social media, with suggestions ranging from Allendale being on fire, UFOs and even the end of the world.

But the source of the light, which was seen from Allenheads, Allendale, and Haltwhistle, has now been revealed as safety tests at Spadeadam research and testing site near Gilsland.

Oil and gas company DNV GL confirmed safety tests performed by the company were behind the flashes.

A spokeswoman for the company said: "We were conducting some critical safety tests on subsea oil and gas valves.

"The primary purpose of the tests is to ensure that the valve would isolate the gas flow in the event of an emergency.

"The testing requires the flow of gas over its operating range. For safety reasons, the gas was ignited and consequently flames were visible some distance from the site.

"Some people reported seeing these flames some distance from the site. Each test lasted 45 seconds and 28 tests were performed over the period of a week."

The RAF Spadeadam range will be a hive of activity this week too, with aircrafts taking part in night flying exercises until 8pm each day from March 18 to March 22.