Opening on Friday 5 September ahead of the anniversary of Elizabeth's birth on 7 September 1533, newly installed stairs and platforms will give a whole new perspective on one of Elizabethan England's finest buildings.

Commissioned by Elizabeth's great love the Earl of Leicester Robert Dudley in the 1570s, Leicester's Building was created for the exclusive use of the queen on her visits to Kenilworth Castle. Housing Elizabeth's private chambers the building was, at the time of her 1575 visit, one of the most spectacular works of architecture in the country - boasting enormous glass windows and all the luxury and elegance that a queen might command. The building has stood as a shell of its former self since the 1650s, only accessible at the basement level.

English Heritage has now installed a series of stairs and platforms within the ruined shell, taking visitors 18 metres high, right up into the queen's private chambers including what was her bedroom, with glimpses into her private staircase, and the long gallery designed for contemplation with close intimates. The new stairs and platforms now bring visitors face-to-face with Elizabethan fireplaces, doorways and other fascinating architectural features, from the building's construction and decoration.

The greatest revelations though are the views from the same vast windows from which Queen Elizabeth I looked over the wooded park and mere surrounding the castle and contemplated the hunts and entertainments that Dudley would provide for her pleasure while at Kenilworth. Even without an army of courtiers or a programme of elaborate pageants, today's visitors can still easily appreciate the magnificence of the scene that once greeted the visiting queen.

Jeremy Ashbee, English Heritage's Head Curator, said: "Leicester's Building was one of the most spectacular works of architecture in Elizabethan England, a soaring tower expressly built to win the queen's hand in marriage. Now for the first time in centuries, visitors can get right up to the top of this remarkable building and get a real sense of the luxury and views she enjoyed."

Queen Elizabeth granted Kenilworth Castle to Robert Dudley in 1563 and the following year he was created Earl of Leicester. Dudley was a valued and envied royal favourite, her Master of the Horse and the courtier on the most intimate terms with her, sharing Elizabeth's passions for riding and dancing. It was no secret in Court circles that he was a suitor for the queen's hand in marriage.

The earl spent a fortune transforming Kenilworth Castle to ensure it was fit to receive his queen and her court, building her a palace and creating a pleasure garden - both expressly for her private use. Elizabeth visited Dudley and Kenilworth several times on her famous summer progresses away from London. Her fourth and final visit in 1575 lasted for 19 days, the longest she had ever stayed at a courtier's house.

Whilst those 19 days of banqueting, hunting parties and pageantry was the talk of Tudor society, Elizabeth never returned to Kenilworth and Dudley failed to win her hand in marriage. But he and Elizabeth remained on the best of terms. In 1588 Leicester was closely involved in the military preparations which resulted in the defeat of the Armada; afterwards he was seen riding in splendour through London, and he dined every day alone with the Queen, something unheard of before. On 4 September 1588, he died while on his way to Kenilworth. Elizabeth locked herself in her apartment for a few days. She kept the letter that he had sent her only six days before his death, and wrote on it 'His Last Letter'. She put it in her treasure box at her bedside, and it was still there when she died 15 years later.

After the Civil War, Leicester's Building and its glorious apartments which once tempted Elizabeth to Kenilworth were left in ruins and until now, the building has stood as a shell without any means of reaching the top. The new stairs and platforms mean visitors can get right up into the queen's former rooms, imagine them in their heyday, and appreciate the magnificent views that were deemed fit only for a queen.