It was 9:18 on 17 march 2020. we were in lockdown due to the coranavirus pandemic. bristol airport was only receiving 2 flights a day from dublin. i know this because my wife is an immigration and customs official at the airport. in normal times planes and chemical trails across the sky would be commonplace. in 2019 we had a loft extension. this is now our bedroom and we have some fantastic views over the city. on the 17th may i looked out our west facing skylight window and saw this strange line going up vertically near a block of flats. i showed my wife the line, then as she stepped away i caught a glimpse of a black domed saucer like object sitting just above what i assumed was chemical trails. i called my wife. when my wife came backthen object had reached the clouds and continued up. oddly in the darker clouds the chem trails seemed to be lighter as it went up. the movement of the object was pulse like, it spurted for a distance, then slowed, then spurted again. this seemed to be the pattern of propulsion. it was vertical, so not similar to the aircraft that would normally fly over horizontally. i instantly checked the flight radar app. no planes were flying in the area due to lockdown apart from a flight which was at bristol airport from dublin. i then checked my night sky app which wasn't showing any abnormalities. around an hour later venus became visible slightly to the right. i had been watching venus move across the west for the last 3 months, so was very familiar. the night was still, cool 11c, no smell, although out of range, no sound. no military vehicles were near by on flight radar and no known rocket launches in cardiff, portishead or bristol because rocket launches don't happen in the uk. a drone seemed unlikely given the chem trails.