Steve Dixon BBC News Online reporter

A mother whose teenage son has been missing for nine months has appealed for him to be in touch for Christmas.

Cheryl Davies is heartbroken she has not heard from her boy, Robert Williams, 16, since he walked out of the family home in Resolven, near Neath, in March this year.

The helpline's poster on Robert Williams

Robert, who is 5ft 4ins tall, slim, with mousey blond hair, is still believed to be living in south Wales as it is thought he was spotted a couple of times in the three months following his disappearance.

His mother said: "It's been very hard to cope with.

"I've got to be strong for his brother as well, he misses him terribly, the same as me.

His details are logged with The National Missing Persons Helpline, a database of the tens of thousands of people who disappear in the UK each year.

It is a catalogue of heartache for thousands of families, some of whom have spoken to BBC News Online about the anguish they suffer at not knowing what has happened to their loved one.

Perhaps the best known missing person in the UK this Christmas remains the former Manic Street Preachers guitarist Richey Edwards.

Richey Edwards: Family's hope

His family have never given up the belief the pop star, who vanished from a London hotel on 1 February 1995, is alive somewhere.

Edwards visited his Cardiff flat the day he disappeared but then a fortnight later his car was found abandoned at the old Severn Bridge services near Aust.

There have been alleged sightings of him round the world, but nothing has been confirmed.

At least his family can draw some comfort from the fact that the rock musician has a public profile which can help in their efforts to locate him.

Most families have to rely on their own efforts and those of agencies such as The National Missing Persons Helpline, which is issuing a seasonal appeal for help in finding the people on its books.

Among those still missing for Christmas 2002 is Roger Evans, a former miner from Stoke-on-Trent who was studying for an economics degree at Aberystwyth University.

If ever she went out of the house, she used to leave out notes in case Roger came back while she was out Roger Evans' sister, Lyn Booth,

Mr Evans vanished in January 1996 just days after ringing his mother with good exam results.

His family say the hardest part about the mystery is not knowing what happened.

His sister Lyn Booth said her brother's car was found on Broth beach a few miles from the university at Aberystwyth - but there was no indication if Mr Evans had drowned or if he had disappeared in some other way.

"My mother died of a broken heart four years ago, which was terrible," said Lyn.

"If ever she went out of the house, she used to leave out notes in case Roger came back while she was out."

A year after he disappeared, the family was told a man had confessed to murdering Roger, but it turned out to be a false report.

The Evans' distress is renewed each time police discover a body and go through their missing persons records.

Dobir Miah: Family man

The case of Dobir Miah is one of those which has been added to The National Missing Persons Helpline.

Mr Miah, a successful young businessman from Swansea, disappeared after taking a taxi ride to Neath from his home six months ago.

Restaurant manager Dobir Miah, 29, told his mother on 8 June this year he was going out.

He took a taxi from their home in Swansea to Neath and he was last seen alive by the taxi driver.

And then nothing.

His bank account and credit cards were untouched and no-one answered calls to his mobile phone.

CCTV footage shows him getting out of the taxi and then returning to pay the driver after getting change for a �50 note.

Not knowing is the hardest part for my family Kabir Miah

His brother Kabir said it was totally out of character for Dobir not to contact his family.

A co-owner of the Jaipur restaurant in Porthcawl, Dobir was also the head of his family following his father's death 17 years ago.

"He was a model brother and father figure," said Kabir. "He has never lived away from home. To be honest, our hopes are dimming. Not knowing is the hardest part for my family."

Another family facing the heartbreak of Christmas without their loved one is that of Ellen Coss who disappeared three years ago en route from Manchester to Holyhead, north Wales.

Mystery

She was depressed following her mother's death and her brother Tom believes she may have gone to Wales.

But there has been no word from her since.

Her disappearance is yet another mystery the National Missing Persons Helpline wants to solve.

If you have any information that could help assist any of these cases, call the National Missing Persons Helpline on 0500 700 700.