Two Willow Road is somewhere that looks pretty ugly from the outside. Some may disagree with my analysis, but to me this modernist terrace sticks out like a sore thumb against the pleasant neighbouring Victorian houses, which incorporate on their brickwork interesting, varied designs and shapes. There’s none of that here, with windows that have boring, functional frames – and on the ground floor level, external concrete pillars protrude.

Two Willow Road, Hampstead

But step inside Two Willow Road and, although some of the fixtures and fittings seem a bit dated, the late 1930s house comes across as way ahead of its time. It’s a compact home, split across four floors that has been designed to make the very most of the space available – and virtually every corner of the house is gloriously filled with light.

Built by the Hungarian Erno Goldfinger – one of the first architects to consider reinforced concrete as a material in its own right – as his family home, the Hampstead property is now in the hands of the National Trust. For most of the time access is by volunteer-led tour only, which has both its benefits (the guide leading my tour was very knowledgeable) and drawbacks (you can’t book in advance and if you’ve just missed a tour you have to hang around for at least an hour).

The lower ground floor is closed off as there is a private still-lived in flat which was previously the servants’ quarters and on the ground floor there’s little of interest to see (bar a toilet without an attached cistern, it’s in the garage to save space, and the hallway is probably the only dark spot in the house). It is therefore after heading up the spiral staircase one level that you start to truly understand Goldfinger’s thinking.

There are three main rooms on the first floor of the house which, although all have their own doors opening onto the central landing, can actually be turned into one large open space. Goldfinger enjoyed hosting parties for his friends and, by folding back internal partitions he would be able to comfortably entertain a large number of people. The fact that it featured a concrete frame meant there was no need for internal walls to provide structural support.

Light fills the two first floor rooms at the front of the house – the dining room and Goldfinger’s wife’s studio (later his office) – thanks to a panoramic window overlooking Hampstead Heath. The large frame looks pretty ugly from the outside, but it’s when you are inside the property that you can see why he wanted to install it from a practical point of view.

Goldfinger designed much of the furniture himself, which, like the overall design of the house itself, puts an emphasis on making the very most of space. Some of the storage units – like the pivoting drawers that fold out from a desk – wouldn’t look out of place in an Ikea showroom today. I couldn’t get excited about much of the modern artwork that the fills rooms, but there were some exceptions, such as a piece by an Italian artist which is appears as a different painting depending on what angle you are looking at it from.

On the floor there is the master bedroom, with a low-level futon (again, very Ikea), built-in wardrobes (way ahead of its time) and an ensuite bathroom (this is one aspect of the house that looks dated, rather than futuristic). The second bedroom is a bit smaller than the main one, but Goldfinger again made the very most of space by adding a single bed that folds down from the wall so can be packed away when not in use. And thanks to internal folding partitions, the nursery could either be one large room or three separate ones.

Celebrated architect

The hour-long tours of Two Willow Road start with 15 minute film about the life and work of Goldfinger, shown in one of his garage’s (he built his house to have two, one of which had an inspection shaft allowing him to look underneath his car).

Born in Budapest in 1902, Goldfinger moved to Paris at the age of 18 and enrolled to study architecture at the Ecole des Beaux-Arts. He married in 1933 the English women Ursula Blackwell, who had been born into the family that had made its fortune from Cross & Blackwell soups. The year of their wedding was also when their first son, Peter, was born.

The Goldfingers moved to London in 1934, with Ernie setting up an office in Bedford Square and they took a three year lease on a flat in the modern Highpoint I in Highgate, which had been designed by the architect’s rival Berthold Lubetkin. When it was time to move on from there they decided to build their own family home and began searching for a suitable plot of land.

They settled on the plot in Hampstead – then an area popular with artists and left-wing idealists – which was occupied by four small cottages, near the newly rebuilt Freemasons’ Arms (now a gastro pub). The first plans they submitted for a block of flats, with studio space for architects, was rejected by London County Council. Another design with four terraced houses was then created, but the one that got the go-ahead features three homes – the Goldfingers’ larger one in the centre and two smaller properties that they sold on either side (both of these are in private hands).

But the planning approval process at Willow Road was not without controversy and the story even made its way into the national press. There were protests from Henry Brooke, secretary of the Heath and Old Hampstead and Protection Society and later local MP, and others that the concrete design would look out of place in the neighbourhood. Goldfinger sought to convince him and others that very little of the building material would be on display.

No sooner had they moved into their new home in 1939 than the Second World War broke out, but an air raid shelter was built at the end of the garden the two children were evacuated to Canada (the third of the siblings wasn’t born until 1945). They returned after the fighting ended and it became a bustling, with at one stage four generations of the Goldfingers living there.

Although Goldfinger received some commissions before the war, it was after the conflict that he truly made a name for his work, designing offices, industrial buildings and homes. Some of the schemes he was responsible for were vast, such as the 27-storey Balfron Tower (where he lived for two months on the top floor) on the Lansbury Estate, the even taller Trellick Tower in North Kensington and the Ministry of Health’s Alexander Flemming House at Elephant and Castle. And Ian Flemming, the creator of James Bond, named the adversary and villain Auric Goldfinger after Erno.

Goldfinger himself died in 1987 and after his wife later died, the property was given to the National Trust. The organisation had access to many original photographs, so had a good understanding of what it was like when the architect and his family lived here; the rooms are today filled with his books, papers and ornaments all in their correct positions. Some of the fixtures and fittings were brought from his previous house, so some items are pretty fragile and volunteers are – perhaps necessarily – paranoid about things breaking.

I’m not a fan of Two Willow Road’s exterior, but I found exploring the inside of the house fascinating. Whether you like the building style or not, Erno Goldfinger has certainly left his mark on London’s skyline and deserves to be remembered. “The greatest honour that can now be paid to him and his example is carefully to look after his work,” wrote James Dunnett, an architect who worked with him in his later years. And that’s certainly what the National Trust is doing.