As a fiercely proud Welshman, Iolo Williams can probably be forgiven for viewing the border country along the 170-mile Offa's Dyke with a smidgeon of caution.

After all it is along this great stretch of countryside which extends from the River Severn in the south to the sea near Prestatyn in the north, where Wales conjoins with its old enemy - England.

However, this does mean that the border is rich in fascinating history and culture as well as some of the most beautiful countryside in the United Kingdom - something which always brings a satisfied smile to the face of one of Wales's most passionate conservationists.

"It is graced with scenery to die for," says Iolo, who walked along the Dyke with co-presenter and historian Tessa Dunlop for a new five part series for BBC Wales called Border Country with Iolo Williams (Thursday, February 22, BBC Two Wales).

"There are also places which have been designated areas of outstanding natural beauty or of special scientific interest and the countryside around the Dyke is absolutely teaming with wildlife," adds Iolo, who was born in Builth Wells and raised in Llanwddyn, mid Wales. "It's a genuinely beautiful and fascinating place for someone like me."

And as Tessa is there to illustrate, the history of the Dyke itself is just as compelling.

"No one really knows why the English King Offa built the Dyke in the eighth century," explains Tessa, who was born and raised on a farm in the Scottish Highlands and who read modern history at Oxford University before becoming an England-based TV and radio presenter.

"But the ambiguity surrounding the Dyke is what makes it so fascinating. There are plenty of ideas and theories as to why Offa, who I believe was a megalomaniac, constructed this enormous, mind-boggling boundary and even more unanswered questions."

In the first programme in the series, Iolo and Tess stop off at Chepstow Castle - the first of its kind to be built in Wales, and discuss the often harsh and violent treatment of the Welsh by the Normans who occupied it.

They also learn more about the now ruined Piercefield Estate on the banks of the River Wye and how Tintern Abbey became a Mecca for the artistic community in the 18th century.

After visiting the famous Rockfield Studios in Monmouthshire to find out more about the recording of Queen's Bohemian Rhapsody, Iolo asks Tessa about one of the most reviled men in Welsh history - Henry V, who was in fact born in Monmouth.

Throughout the series, Iolo and Tessa will be seen discussing the age old battle between Wales and England. And although the duo don't always see eye to eye, Tessa does have some understanding of the Wales-England dynamic.

"Having been brought up in Scotland I know all about the feelings and fears experienced by those on the Celtic fringes, even though they may be slightly irrational. But all along the Offa's Dyke border we found an ambiguous national identity and many historical and natural curiosities pointing to the complex but ultimately enriching mix of Welsh/Anglo culture."

Border Country with Iolo Williams is an Element production for BBC Wales.