The family of a missing Bradford dad who "simply vanished" have made an emotional appeal for information about his whereabouts.

Detectives say they are "extremely concerned" for 48-year-old David Rowling, who has not been seen since he left his home in Alma Street, Queensbury, last Saturday, taking nothing with him.

Police are carrying out door-to-door inquiries in Queensbury and the force helicopter, equipped with a heat-seeking device, has been used to search Ogden reservoir and Ogden Moor, an area Mr Rowling enjoyed visiting.

Mr Rowling, who has never been missing before, works as an IT consultant in Bradford and lives with his wife Stephanie and three-year-old son Samuel.

Speaking at a press conference, one of his sisters, Brenda Rowling, said: "David, if you're out there, we just want you to contact one of us or anybody and just let us know you're safe.

"Mum would like you to please ring her just to know you're safe. If you've got any problems we can help you sort them just please come home."

Miss Rowling said her brother liked outdoor pursuits such as climbing, walking and had run marathons in the past.

She described him as a warm, caring person and added: "It's just the knot in your stomach trying to think where he could be and what we can do to get him home."

Susan Laycock, his other sister, said: "If anybody has seen David, could they please come forward. This is very out-of-character."

Detective Inspector Steve Snow said: "He left home a week ago he walked out of the door and simply vanished.

"We know that some time after 9.30am on Saturday he left the house and didn't take any possessions with him whatsoever. He left his mobile phone, his wallet and any money that he may have had.

"We know that David was probably feeling a little but down about things in general and having spoken with his wife we haven't yet got to the bottom of why he was feeling pretty low and of pretty low self esteem at the time, which again raises some pretty significant concerns for me.

"I need to piece together the jigsaw because, at the moment, I just do not know where David is.

"We know that he also had an interest in canal boats and he had a canal boat over at Skipton. Again, we have made inquiries over there and that's brought nothing at all at this moment."

Det Insp Snow described Mr Rowling as a "very private family man" who kept himself to himself and did not socialise a great deal.

He said: "When he left the home, he didn't leave in any suitable clothing that you would want to exist in the outdoors with and it has been relatively cold on an evening. I'm extremely concerned."

Mr Rowling is white, 5ft 8ins tall, slim with short grey hair and was wearing an olive-coloured cotton anorak, brown boots, grey or green cord jeans and a green jumper.

Anyone with information should call Det Insp Snow at Bradford South CID on 0845 6060606.