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Harold Maxwell-Lefroy, the founder of Rentokil, was born in 1877 in the village of Crondall in NE Hampshire, only around 10 miles from the current Rentokil Initial headquarters in Camberley. He studied natural sciences at King’s College Cambridge, achieving a first class degree in 1898 and a masters in 1902. It was here that he started a lifelong interest in insects.

Harold Maxwell-Lefroy

After a short time as an assistant master at a school, Seaford College, he took up a post in the Caribbean in 1899 as a lecturer in economic entomology. He was then appointed Entomologist at the Imperial Department of Agriculture in the West Indies from 1899-1903.

He spent several years studying crop pests and advising landowners on crop protection to help them recover from a hurricane that had caused extensive damage in 1899. He published his findings in numerous publications, including the West Indian Bulletin, Barbados Bulletin and the Official Gazette of Barbados. He became a Fellow of the Zoological Society of London in 1902.

Maxwell-Lefroy became the first person to be appointed Imperial Entomologist to the government of India in 1903 and stayed in the post until 1912. During this time he wrote a series of ground-breaking books, including Indian Insect Pests (1906) and Indian Insect Life: a manual of the insects of the plains (tropical India) (1909), an 800-page guide with many hand-painted illustrations and still in print. He also set up the entomology department in the newly created Indian Agricultural Research Institute (IARI) at Pusa in Bihar in 1905, now relocated to New Delhi.

Harold Maxwell-Lefroy

While assigned to India Maxwell-Lefroy married Kathleen O’Meara, whom he had met in British Guiana, and had three children. Tragically two children died of what they believed were insect-borne diseases, so in 1910 he decided to return to England with his wife and surviving child, Cecil. They moved to Strawberry Hill, Twickenham, where he took leave of his government position for nearly two years.

Before he returned to England he had arranged to give a course of lectures on entomology at Imperial College, London. In his inaugural lecture in March 1911 he showed an insight that is still relevant today:

“It is only lately that the significance of the insect world has become apparent. … The opening up to agriculture of new tropical countries, the increasing competition in the cultivation of tropical products, the discovery of the part played by insects in disseminating human disease, have brought entomology to the front and have shown that, far from being a science concerned solely with the minute classification of interminable varieties and species, it is a science which has great significance for man, and one which requires to be developed in serious earnest if we are to be in a position to harvest our crops, to cope with disease, and to populate tropical areas successfully.”

Imperial College appointed Maxwell-Lefroy as their first Professor of Entomology in 1912. The following year he was given the honorary position of curator of the insect house at London Zoo and appointed Entomologist to the Royal Horticultural Society at Wisley in Surrey. 

One of his lectures at Wisley was turned into an RHS pamphlet published in 1916, titled, On keeping fruit trees clean, that was reprinted six times, the last in 1942 (copies are in the RHS library). He held the position of Professor of Entomology at Imperial College until his death in 1925. 

Frank Baines, the Director of the Office of Works (a government department) contacted Maxwell-Lefroy in 1914 to find a method of exterminating death watch beetles infesting the roof timbers of Westminster Hall, at the Houses of Parliament.

Professor Maxwell-Lefroy concocted a fluid that successfully treated the timber, composed of 50% tetrachloroethane, 40% trichloroethylene, 6% cedarwood oil, 2% soap, and 2% paraffin wax. This led to the first idea that there could be a business in timber treatment. 

On the outbreak of the First World War he was sent to India to help revive the silk industry, but also took up the cause of British troops affected by pests such as lice. He was then transferred to the Middle East under the Mesopotamian Expeditionary Force to improve hygiene of soldiers through pest control. This work led to him co-authoring a paper in 1917 on fly poisons for outdoor and hospital use (2). 

For his next assignment he was shipped to Australia to investigate weevil infestations of wheat stored in port in Sydney for transport to the UK. He found that poor storage conditions allowed rain to get onto the wheat, which made it damp and encouraged the weevils. He advised on improving storage conditions and devised a treatment for the grain. 

After the War he returned to his position at Imperial College and contributed to a series of wildlife films, called Secrets of Nature, that used pioneering filming techniques. 

Professor Maxwell-Lefroy also started marketing his timber treatment fluid to architects, builders, furniture makers and antique dealers. He recruited Bessie Eades to run the business and established a company called Disinfectants and General Products Ltd on 29 September 1924. He registered the trademark ‘Rentokil’ for his product, having been refused his first option of Entokill by the Board of Trade. 

At a time when death watch beetles could be a nuisance to church goers because they were such a common infestation in old timbers, it would seem that there was a business opportunity to be exploited.

Years later, however, it was discovered that he had given free advice to over one hundred churches and cathedrals. Even his son later commented that his business instincts were not great and the business was a drain on his finances. 

The Professor tested chemicals for their toxicity on flies in his lab at Imperial College while taking few precautions for his own safety. In October 1925 while alone in his laboratory he was overcome by fumes. He was found unconscious some time later by his wife who was worried because he had not gone home. He was taken to St George’s Hospital in London, but died a few days later without regaining consciousness.

The Annual Report of Council of King’s College Cambridge described his achievements: “During his nine years in India he revolutionised previous methods of studying the insect pests of agricultural crops, he carried out personally and superintended an amazing amount of research of many serious pests, and devised practical remedies.” 

An article in the Morning Post in April 1926 said: "His ambition was by his own efforts and those of his pupils to organise an army of fighting entomologists, men who had been trained to study the habits of pests and who would be capable of applying the knowledge obtained to each economic problem as it arose."


Cambridge Alumni Database (link)

AC. Jackson and HM Lefroy. Some fly poisons for outdoor and hospital use. Bulletin of Entomological Research, Volume 7, Issue 4, June 1917, pp 327-335.

Rob Gray. 2015. The Pest Detectives. Petersfield, Harriman House. ISBN 978-0-85719-507-4

Laurence Fleming, 2015. The Entokil Man. The Life of Harold Maxwell-Lefroy. London, Dexter Haven Publishing Ltd. ISBN 978-1-903660-17-1

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