It's filled with weeds, choked with filth and buried in undergrowth - but the potential of Cardigan Castle and Castle Green House is plain to see.

On a hot June afternoon, Tivy-Side editor Aneurin Evans and deputy Sue Lewis accompanied by heritage officer Gary Cooper were given a guided tour of the castle by local historian Glen Johnson.

After nearly two years of campaigning for the castle to be brought into public ownership we felt as if we already knew every nook and cranny - but photographs and memories couldn't prepare us for the reality. Cardigan Castle is just a step away from the centre of town, but a sense of silence descends as you pass through the main gates.

All around is dense greenery, the once manicured lawns obscured by a impenetrable tangle of briars, nettles and creeping vines. Just visible - almost floating on a sea of lush greenery - is the tiled roof of Castle Green House.

"We'll do the grounds first," says Glen, with the practised ease of a tour guide, honed on years of experience with the Cardigan Castle volunteers in the 1980s.

"Follow me."

With that we push through the undergrowth onto the battlements - the crennellations poking through a cloak of ivy.

What a view.

True, we were balanced precariously on a tiny stone ledge, but the view from the 30ft high walls gave us a new perspective of the River Teifi.

It was easy to imagine ourselves as Welsh lords watching invading armies of Normans rowing up the river. A few paces on we were jolted back into the 20th century with a World War II concrete pillbox squatting squarely on the battlements.

"This must be saved," said Glen.

"It is as much a part of Cardigan history as the rest of the castle."

A few yards on we were catapulted back to medieval times as a stone passageway yawned open between two walls.

Steep stone steps lead down to a medieval privy - where centuries ago, the River Teifi was used as a natural flushing system.

On our way to the East Tower we passed an evocative reminder of more recent times - a tennis post encased in ivy.

"There used to be a tennis lawn right here," said Glen, gesturing at dense bushes and clumps of saplings. Images of 1920s flapper girls in white cloche hats lazily batting a ball to and fro weren't hard to conjure up - but what would they say if they could see it now?

"Anyone for spare rib?" joked Glen, pointing to what looked like a weirdly-shaped tree trunk. The famous whale rib - one of a pair brought back to Cardigan by a sea captain and placed within the castle for safekeeping.

Plunging back through time, we made our way to the medieval East Tower where Glen pointed out an arrow slit below the tower's ground level - suggesting the possibility of a buried room.

"That's the thing I love about Cardigan Castle," said Glen.

"It's full of surprises. You just never know what you're going to find."

On we walked, pushing aside nettles and brambles, past the front of the house and round the side to the croquet lawn - like the tennis lawn buried beneath decades of growth.

Under a brick arch and round the medieval North Tower to the back of the 18th century East Wing. The rooftops of St Mary's Street were just visible above the trees on the left.

"I'm afraid we won't be able to make it to the coach-house," said Glen, surveying the towering bramble barrier. The stables also suffered the same fate - choked in a mass of undergrowth, although we managed to peer into the castle well.

We paused to lean on the wall overlooking the garden - or what was once a garden - backing onto Carriers Lane.

It was quite a shock to see cars moving along the road - after an hour of walking around the tranquil castle grounds, 21st century reality seems a long way away.

"Right, are you ready for the house?" asked Glen.

Grabbing our torches, we set off after him.

Inside Castle Green House - see next week's Tivy-Side.