And in 1978 the trust played a leading role in preventing a pump drainage scheme at Amberley Wildbrooks, a widely reported success which helped to turn the tide in favour of preserving the natural environment.Although Penfold stood down as chair in 1988 he remained a regular attendee of the trust's council In later years he grew deaf. With his help the trust acquired important nature reserves at the Mens, Ebernoe Common and Pevensey Marshes. However he trained in commando techniques as one of a secret force that was to go underground in the event of an invasion and sabotage enemy communications. The life expectancy of such resistance fighters was only a few weeks.A keen naturalist from boyhood, Penfold joined the Sussex Wildlife Trust at its inaugural meeting in 1961 and two years later was elected Chairman. The history of the firm, Penfolds of Arundel: agricultural engineers 1833-1983, which Penfold wrote to commemorate its 150th anniversary four years earlier, is effectively a short history of agriculture in Sussex.Penfold was in a reserved occupation when the Second World War began. Over his working life in the family business, Penfold saw the revolution in agricultural machinery from the steam-driven rollers and threshers of his youth to the high-power tractors and combine harvesters of today (Penfolds introduced combine harvesters to Sussex).The company thrived in the post-war boom years but in the 1980s, by which time Frank was assisted by his eldest son, John, the agricultural supply industry was failing nationwide The firm closed in 1987.

In 1833 his great-grandfather had set up the family business of Penfolds of Arundel, which began as a forge and ironmonger's shop. Long before the 20th century it had established a county-wide reputation and supplied the very latest in farm machinery.After being educated at Midhurst Grammar School and serving an apprenticeship at Listers of Dursley, Gloucestershire, he joined the company in 1933. One of his characteristic qualities was perseverance: once he had begun something he always tried to see it through to a conclusion. His gruff charm and high standing in the local farming world made him an effective bridge between the farming community and the conservation body He is said to have known practically every farmer in Sussex Moreover he talked their language.

Many conversations that began in heated argument mellowed into friendly reminiscences of the harvest, steam ploughs and mutual acquaintances.Frank Penfold was born into an old Sussex family of yeoman farmers. An agricultural engineer by profession, he was also a man of Sussex whose family had lived for generations within a few miles of Arundel. With his mind for business, Penfold was meticulous and well organised. Re-elected to the post every year for a quarter of a century, he presided over the growth of the trust from its formative years to the successful and influential body of today. Frank Penfold was the long-serving chairman of the Sussex Wildlife Trust.