The last confirmed sighting of Jack was at about 3.15am in the area of Brunel Lock Road/Brunel Way of Bristol (as marked on the map provided to the right of the screen).

Jack O'Sullivan was last seen walking near Bristol's city centre, along Brunel Lock Road, at 03:15 GMT on Saturday 2 March after attending a house party, possibly a birthday party in Hotwells.

His parents report:

"We've been able to ascertain his movements of leaving the party at around 02:53, seeing him attempt to stop taxis and Ubers, and trying to get a lift on two occasions," his mother said.  She added, she had waited up for her son but fell asleep after receiving a text from him at 01:52, assuring her he would find an Uber home.

At 03:24, Mr O'Sullivan had attempted to make a call to a friend who was still at the party Jack attended.

When the friend called back 10 minutes later, Mr O'Sullivan answered but only managed to say "hello" before the line went dead, Avon and Somerset Police said.

However, his phone remained active on the Find My Friends app up until 06:44.

"To go off camera and vanish is one thing, but the phone for us, as awful as this terrible situation is, is the big unanswered question," Mrs O'Sullivan said.

Police have released a CCTV image showing another possible sighting of Mr O'Sullivan, spotted near Hotwell Road at about 05:40.

There has been no contact with Jack since.