Iolo Williams will lead the 250-mile fundraising trip

The walk will raise funds for Hope House charity and Ty Hafan hospice in south Wales - the two chosen charities for S4C's 2003 appeal.

Oswestry-based charity Hope House unveiled its plans for a north Wales unit last year.

Work on building Ty Gobaith, a five-bed hospice in Ty'n y Groes near Conwy is due to start in the spring at a cost of �2m.

Iolo Williams, who has presented nature programmes such as Wild Wales, Birdman and Crwydro, will be joined on his journey by S4C weatherman, Chris Jones, and experienced mountaineer, Dewi Evans, from Bala.

Members of the public are also being asked to register for the 11-day journey which begins on 15 June at the site of the new hospice overlooking the Conwy estuary.

There will be an opportunity for 20 people to walk with them every day, provided each raises at least �250 in sponsorship.

Ty Gobaith is scheduled to open in 2004

The route will take them from Conwy through Capel Curig, Beddgelert, Bala, Lampeter, the Brecon Beacons and Merthyr Tydfil before arriving in Cardiff Bay along the Taff Trail and ending at Ty Hafan in Glamorganshire.

Iolo Williams said: "I have two small children of my own so I know how important it is for parents that the right support and facilities are available if their children become ill.

"I'm looking forward to the journey.

"I enjoy a challenge - whether it's mountain climbing, running, biking or sailing - but trying to walk over open country across the whole of Wales will be something else!" he added.

Television

Ty Gobaith fundraiser, Sarah Jones, said more than �1m has already been raised for the new north Wales hospice.

"The support from schools, businesses and the general public in north Wales has been fantastic and we are well over the halfway mark towards �2m.

"We will be laying the foundations in a few weeks time and hope to open our doors to children in the spring of 2004," she said.

As well as two celebratory dinners at the beginning and end of the journey, there will be fundraising activities en route, including parties in Bala and Dolgellau.

An S4C spokesman said they hoped to raise as much as �50,000 during the journey which will be filmed for Welsh television.

Anyone interested in joining the walkers are asked to contact either S4C or Hope House in Oswestry.