I spent the perfect rainy afternoon at one of the West Midlands' most impressive country mansions - for free

Between September 12 and September 21, hundreds of historic venues around the country are throwing open their doors in a celebration of England's history and culture with Heritage Open Days.

While various venues are offering special tours or exhibitions for the event, for many the festival means free entry to dozens of castles, manors and country houses usually locked behind a real-life paywall. 

I never pass on a bargain, so to take advantage of the offering, on Sunday I opted to spend a drizzly couple of hours at Dudmaston Hall. 

The grand 17th-century country house is located a few miles south of Bridgnorth near the village of Quatt, just off the A442 on the way to Kidderminster. 

I expected to join hundreds of others scrambling to get in to Dudmaston for free (usually £16.50 for adults without a National Trust membership), but the looming grey clouds and incoming yellow weather warning kept most of the crowds at bay. 

Dudmaston is a working estate, still occupied by the same family (in a vague sort of way) that moved in more than 800 years ago. 

In 1978 the estate was gifted to the National Trust, with the request that the grand hall remain a family home forever. 

Today, Dudmaston Hall is the beloved home of the Hamilton-Russell family: Mark, Elfrida, Rachel and Oscar.

Around two thirds of the grand mansion is open to the public for around three hours, five days a week for much of the year. For the rest of the time, the family get free rein. 

It feels like a family home too, with intimate pictures nestled among grand paintings of their wigged and ruffed ancestors.

Eager volunteers in almost every room happily point to their favourites, regaling visitors with proud tales of life achievements as they would with dog-eared photographs pulled from their own wallets. 

The journey through the home feels like one of two halves: at first you're greeted by the timber-panelled rooms and chandeliers you'd expect in any other country house, but travel up the stairs and round the landing and - slightly bizarrely - you're transported to a modern art gallery, featuring works by artists including Barbara Hepworth and Henri Matisse.

Described as one of the most important private collections of modern art in Britain, Dudmaston's galleries were installed by Sir George and Lady Rachel Labouchere, who bestowed the estate to the National Trust in 1978.

As part of the collection, there's an entire room dedicated to art made in the aftermath of the Spanish Civil War, and the walls are filled with anti-establishment artwork.

It's an interesting juxtaposition to be stood in a grand country home, staring at artwork critiquing 'the man'. 

But it's a type of awkwardness that Dudmaston embraces, in what it calls an "unexpected unity" or a "fusion of old and new".

Like many other country homes I've visited, Dudmaston's real beauty is found outside. 

The estate's extensive art collection extends into the garden, with sculptures scattered throughout the impeccably maintained grounds. 

Dramatic terraces overlook a stunning lake towards the Clee Hills - still slightly visible even on my drizzly Sunday visit. 

I could have wandered for several hours, and would have done, if the wind hadn't started to pull at the umbrella that was already barely protecting me from the increasingly angular rain. 

Luckily, shelter was to be found in the tea room and second-hand bookshop, where my hours were spent instead.

Dudmaston is free to enter today (September 18) and again on Sunday (September 21) as part of the Heritage Open Days festival. 

Learn more on the Heritage Open Days website.