Mr Blake went missing in the Black Mountains on 13 May

Mr Blake's daughter Elaine Jones - the pair are from Cheltenham - said it was unusual for him not to tell his family his whereabouts.

"The most difficult thing is just not knowing where he is," she said.

"He is a very keen walker and, despite his age, he is in good shape and would often going walking."

Weather worse

Mr Blake was last seen in Hay Bluff on Monday afternoon by another walker, who later said weather conditions had been worsening in the area.

His family raised the alarm Monday after the walker failed to give his children his daily 1800 BST telephone call.

Gwent Police officers are now contacting the hundreds of bed-and-breakfast hostels in the area in a bid to trace the widower.

They said earlier the OAP made a call to a B&B on Monday morning to make a booking for that night but he never arrived.

Detectives repeated appeals for local people to search sheds and garages for signs of Mr Blake.

"He does not know this area very well but he had very detailed maps," Ms Jones added.

"We are worried he has got confused and disorientated.

Mobile phone

"My father also had his mobile phone with him but he has not made a call from it since Monday morning and it is not switched on."

"It is just appalling now knowing where he is or what has happened."

Search team leader Ewan Thomas said while hope remained of finding Mr Blake alive, the search would continue.

On Wednesday, that search covered 44km of the huge national park.

Mr Blake was last seen wearing blue waterproof trousers, a tweed hat and carrying a rucksack.

Gwent Police said the search is ongoing and appealed for anyone with information to telephone 01633 838 111.