It is an eagerly anticipated story of Tudor England, but BBC historical drama Wolf Hall was initially going to be filmed in Belgium, partly because it was expected to be cheaper.

The budget for the Tudor epic based on Hilary Mantel’s Booker prize-winning novel, which airs on Wednesday evening, had been calculated to take advantage of Belgian tax breaks for film-makers.

However, director Peter Kosminsky said the proposed foreign backdrop simply didn’t look right.

“Shooting in these sort of European castles that look like something out of Grimm’s Fairy Tales, very tall steep tiled roofs that just don’t look like Tudor England at all,” he said.

Other recent BBC period dramas have been filmed in Belgium – most notably The White Queen, set 70 years earlier, where the country’s medieval buildings are arguably better preserved than their British counterparts.

In any event, any clash between artistic fidelity and financial prudence was averted when George Osborne introduced tax breaks for high-end drama in April 2013, making it straightforward for the production as it chose location shots in English period buildings such as Montacute House in Somerset and Penshurst Place in Kent.

In the runup to the broadcast of the drama, the BBC has been emphasising its historical accuracy. From shooting by candlelight in Tudor buildings to weaving fabrics for costumes, every aspect was discussed to make the programme look as authentic as possible.

Mantel praised the “unseen army” of people who worked on the six-part adaptation, which amalgamates her two Booker-winning novels Wolf Hall and Bring Up the Bodies.

“I spent a fascinating hour or two in the trailers with the costumes, turning them inside out and examining every stitch. The leather was aged, the fabrics were specially woven.

“Even the pins were specially handmade to an authentic pattern, and my husband is carrying one around in his wallet as a sort of talisman; pins held the Tudors together,” she told the BBC.

“There’s no doubt that an unseen army was at work behind the scenes, on every aspect of the production, and I owe them gratitude.”

The six-part series tells the story Thomas Cromwell’s rise to power in the court of Henry VIII and is one of the jewels in the crown of the BBC’s 2015 programming. The big budget approach is reflected in a high-quality cast led by Mark Rylance as Cromwell, with Homeland star Damian Lewis as Henry VIII, Claire Foy as Anne Boleyn and Jonathan Pryce as Cardinal Wolsey.

The key driver was Kosminsky, who is renowned for his attention to detail in fact-based dramas such as the award-winning The Government Inspector and Shoot to Kill. He told the Guardian that he said to Wolf Hall producers Company Pictures: “I want it to be really accurate … I want the costumes to be right, the look to be right. I want this to be thoroughly researched.”

Kosminsky and his cameraman then began testing different cameras and lenses to see if they could film by candlelight. They looked at a number of artists and ended up trying to achieve the lighting effects created by the Italian painter Caravaggio at the end of the 16th century.

They also experimented with various candles to see which would create a very white light, even trying out tallow candles of the period.

The drive for authenticity had an impact on the actors, says Kosminsky: “If you think about Damian Lewis playing Henry and Claire Foy playing Anne, standing in the gallery in Penshurst Place knowing that 500 years ago the real Henry and Anne stood in that room and it’s a night scene and the room is lit as it was built to be lit, by candlelight – there is an extraordinary frisson for them as actors and us as crew about doing that.”

That frisson had to be offset by the tour parties that every so often the crew had to allow through, as “that was the only basis on which we were able to use those spaces”, but the tradeoff was worth it.

There has been only one complaint so far about the extraordinary lengths the production went to be true to the period, with Rylance joking that the authentic cod-pieces were too small.

But, as Mantel says in Wolf Hall, “Beneath every history, another history” and, against the backdrop of the drama’s political intrigue, the BBC is about to become embroiled in political manoeuvring of its own. There is much at stake at the moment for the corporation after the election. Director general Tony Hall warned recently that the BBC is entering a period of “high risk” as it navigates the renewal of the royal charter that dictates how it is funded and how big it should be. With a season of complementary programmes wrapped around it, Wolf Hall is one of the key planks in the BBC’s drama output this year.

After a visit to the drama’s set during filming, Hall described it as “very powerful and very special”. Its authenticity and intellectual credentials will undoubtedly send out a message to political circles as to the type of high-end drama a well-funded BBC can produce.

• Wolf Hall begins on BBC2 on 21 January

Show’s shining stars – the teeth

Even the gleaming teeth in the BBC’s adaptation of Wolf Hall are historically accurate, according to author Hilary Mantel, who says that in an age when eating sugar was uncommon – even for the likes of Henry VIII – tooth decay was much less of a problem.

“You do not have bad teeth, and you are not dirty,” the Sunday Telegraph reports her assuring the cast. “There are two ways in historical drama: either glamorise them impossibly, or rough them up in some picturesque way so they all have bad teeth.

“Which, actually, at that stage in history people didn’t have, because they ate so little sugar.

“You don’t want to glamorize the past, but you don’t want to belie it by making it grotesque. Because in that way the viewer or the reader starts to patronise the people, and think we’re more advanced than they were, and condescend to the past.”

Although some BBC costume dramas, including the Plantagenet era The White Queen, were mocked for the characters’ immaculately white, straightened teeth, historians agree that extensive sugar imports from the New World only came later in the Tudor period – by the end of her life Elizabeth I was reported to have blackened teeth, always omitted from the official portraits.

Maev Kennedy