IT WAS living within spitting distance of two of London's country houses that inspired architectural historian Caroline Knight to write about the capital's historic gems. I lived next door to Cromwell House in Highgate Hill when it was occupied by mo

IT WAS living within spitting distance of two of London's 'country' houses that inspired architectural historian Caroline Knight to write about the capital's historic gems.

"I lived next door to Cromwell House in Highgate Hill when it was occupied by monks and I got curious about it when I went to charity sales and open days there," says Knight, who now lives in West London.

"Living opposite Lauderdale House I used to take my children for walks in the park and it got me interested in researching who had built these houses and why."

After researching the topic for her MA at The Courtauld Intitute, Knight has now extended her study for London's Country Houses, (Phillimore Press �30)

She focuses on important surviving examples of suburban grand houses within the M25 - near-London homes built to enable the families of wealthy traders, bankers, lawyers, courtiers, parliamentarians and aristocrats to escape the polluted, overcrowded city centre.

"They favoured places like Hampstead and Highgate on a hill with nice views, good air, fresh springs and gardens to grow fruit and vegetables," she says.

"They were not like rural country houses - they were more compact, not on huge estates and were less likely to be the ancestral homes of aristocratic families. Many who built them were City families who bought land as an investment and built houses as an escape for their families from central London, particularly in the summer when there was a lot of plague and fever. There could be several large houses in the same parish."

Although riverside places such as Richmond, Kew and Twickenham were also popular, Highgate became highly desirable in the 17th Century because its position on the Great North Road gave owners quick access to The City.

As roads improved and the city developed westwards, Hampstead became more popular in the 18th Century.

Many important houses such as Dorchester House in Highgate and Belsize House, in what is now Belsize Park, were swallowed up by urban growth, but Knight mostly focuses on those that have survived. Some, like Kenwood and Fenton House are run by heritage organisations as musems, others have become offices, hotels and other institutions such as golf clubs and FE colleges. A few are empty and under threat. Some survive but stand as historic oases, surrounded by industrial sprawl.

Local authorities often bought them to preserve public open space saving them from destruction by making their grounds into public parks.

A few are still in private ownership including Syon House which has been in the Percy family since 1594, and Canonbury which hasn't been sold since it was bought by Sir John Spencer in 1570. Those lost include The Old Palace at Bromley by Bow whose destruction in 1893 alerted conservationists to the threat to London's historic houses.

North London properties include: BEECHWOOD and THE ELMS: Built on adjoining plots by George and Nathaniel Basevi, Anglo-Jewish brothers related to Benjamin Disraeli. George, a gifted architect who designed both houses, worked for Sir John Soane before setting up his own practice.He died at the height of his career after falling from the tower of Ely Cathedral. His widow sold the house soon afterwards.

LAUDERDALE HOUSE is the oldest surviving timber framed house in Highgate and was built around 1580 by City goldsmith Richard Martin, the son of a Lord Mayor. The house was bought in 1641 by the Dowager countess of Home but she was forced out during the Civil War by Cromwell's son-in-law. Her daughter, Lady Lauderdale, reclaimed it after the restoration and she and her husband gave their name to it.

It became a school in the late 18th and early 19th centuries before being bought in 1865 by Sir Sydney Waterlow, printer and Lord Mayor. The interior was badly damaged by a fire in 1963 and it has been run as a community arts centre by Camden since 1971.

FENTON HOUSE was built in 1686 by bricklayer William Eades. The house got its name from merchant Philip Fenton who moved in in 1793. He bequeathed it to son James in 1807 who made several alterations and additions but over the next 100 years the house changed hands many times. It was bought in 1936 by Lady Binning who bequeathed the house, including some fine furniture and porcelain to the National Trust upon her death in 1952.

CROMWELL HOUSE was built in 1637 by Richard Sprignell who hailed from a City family of barber surgeons. A wealthy Royalist, Sprignell was a captain of the Trained Bands and was made a baronet by Charles I in 1641. His son sold the house and 19 acres in 1664 and 11 years later it was bought by Portuguese merchant Alvares da Costa, the first Jew to own property in England. In 1865, a fire destroyed the top floor but it was repaired and from 1896-1923 it was a convalescent home for patients at Great Ormond St Children's Hospital. The Mothercraft Training Society bought it in 1924 then several missionary societies owned it before selling it on. In 1989 it became part of the Ghanaian Embassy.

The land on which KENWOOD HOUSE is built was originally owned by the Priory of the Holy Trinity Aldgate. King James I's printer John Bill bought 460 acres in 1616 to build a family retreat. In the early 18th Century it was bought by the 2nd and 3rd Dukes of Argyll who later part owned it with their brother in law the 2nd Earl of Bute. His son bought out the Argylls because he needed a London home as he had a position at the court of Frederick Prince of Wales. A keen gardener, he built the orangery but sold the house in 1754 to William Murray, later 1st Earl of Mansfield, who commissioned Robert and James Adam to enlarge it in 1764. Given a free hand, their interior and exterior designs proved highly successful. Mansfield, who had no children died at Kenwood in 1793. His nephew David Murray commissioned architect George Saunders to make further changes including adding a dairy and model farm. The Mansfields owned Kenwood until 1922 when the house contents were sold and much of the Adam furniture dispersed. The fourth Earl had previously sold 201 acres including Highgate Ponds and Parliament Hill fields to the Metropolitan Board of Works to be added to the Heath. But when the 6th Earl later tried to negotiate sale of the remaining estate for development the public protest inspired the Kenwood Preservation Council to raise enough to buy the woods opposite the house. They were opened to the public by George V in 1925.

The house however lay empty and came under threat until Edward Guinness, 1st Earl of Iveagh stepped in. He died two years, leaving it to the public and it opened in 1928 as The Iveagh Bequest. It is now run by English Heritage.