Kenwood House is a North London treasure. Perhaps it’s because of its position, right at the top of Hampstead Heath, gazing down over the rest of the city; perhaps it’s because, thanks to the terms of the Iveagh Bequest, it’s free to visit and always will be. Or perhaps it’s just because it’s so lovely.

Kenwood House was built in the early seventeenth century but it’s transformation from a prosaic house into a masterpiece was due to Robert Adam, who remodelled it in the 1760s. It’s a pinnacle of the ‘Adam style’, which uses decorative motifs based on the domestic architecture of ancient Rome, as opposed to the public buildings that influenced the Palladian style.

It’s home to the paintings from the Iveagh Bequest, an internationally significant collection of Old Master and British paintings by artists including Vermeer, Rembrandt, Gainsborough and Reynolds.

The library is easily the most impressive room in the house – not surprisingly, it’s regarded as one of Adam’s greatest interiors. It’s in neoclassical form with a decorative frieze and ceiling paintings by Antonio Zucchi, and the recent restoration accurately reproduces Adam’s original colour scheme.

The antechamber to the library is also by Robert Adam. The original furniture of the house was all sold in 1922 but is gradually being traced and reacquired. Two of the original four benches in the antechamber have been bought back.

This French bracket clock dates from 1700. It’s ormolu boulle (gilt bronze inlaid with tortoiseshell and brass) The figure on top is Mars, God of War. It was bought by the 2nd Earl of Mansfield when he was Ambassador to Paris from 1772 to 1778.

The clock sits in a corner of the small Green Room, which leads into the Music Room.

The 2nd Earl of Mansfield added the Music Room, when he remodelled the house between 1794 and 1796.

It contains important works by Thomas Gainsborough, including this portrait of Mary, Countess Howe.

The windows of the Breakfast Room on the south side look out over the lawn and down to the artificial lake.The painting is Miss Cocks and her niece by Joshua Reynolds.

The chinoiserie chimneypiece in the Chinese Room upstairs was designed by Robert Adam ( the actual design is now in Sir John Soane’s Museum). It has painted marble tiles and carved decorations showing mermen, cherubs and seahorses.

Kenwood House is open daily from the end of March to the end of September. It’s owned by English Heritage and it’s free. The 210 bus passes the door.