As a temporary emergency war-time measure in 1943, under the (Amalgamation of Police Forces) Regulations, 1942, on 1 February the Guildford Borough Police and Reigate Borough Police were amalgamated with the Surrey Constabulary under the title of the Surrey Joint Police Force.

Major G Nicholson M.C., the Chief Constable of Surrey Constabulary, was appointed by the Home Secretary as the Chief Constable of the new Surrey Joint Police Force. The Chief Constable of Guildford, Mr Walter Oliver, retired from the service and the Chief Constable of Reigate Borough Police, Mr W H Beacher, was appointed the Superintendent of the new Reigate Borough Division of the combined force. Chief Inspector Ashley T Steeds, of the Guildford Borough Police, became the temporary Superintendent of the new Guildford Borough Division. All promotions were styled 'temporary' so as to avoid anomalies when it came to restoration of peace-time conditions - as it was repeated over and over by the Home Secretary and his Officials that the merger was only a temporary measure owing to necessities of the War.

The Home Secretary directed that the Surrey Joint Police Force was to be controlled by the Standing Joint Committee of Surrey, to which the Borough Councils of Guildford and Reigate could each appoint two members, an increase of an additional member for each over what had been suggested in the Draft Order of the previous November. The expenses of the Surrey Joint Police Force were paid out of the Surrey County fund, with Guildford and Reigate contributing to that fund in accordance with arranged provisions and proportions.

The Guildford Borough Watch Committee and the Borough Bench of Magistrates remained in existence. Everything used by the Guildford Borough Police including premises, uniform, cars and chattels of all kinds were transferred to the joint authority. There was no change to uniform to bring it into line with that of the Surrey Constabulary as that was deemed unnecessary and wasteful, especially in the light that a return to the status quo was expected after the War. Every precaution was taken to preserve the identities of the three forces, so that post-war separation could be effected with the least possible trouble.

Within the first month after the amalgamation, inspections took place of the Reigate Division and Chief Constable Nicholson addressed the officers on their duties in the Surrey Joint Police Force and Police practise in the County. Assuring them of his personal interest in them and their work, he emphasised that it was not his intention to make drastic changes. If changes came, they would be only for the efficiency of the service, for discipline or for promotion.

Temporary promotions and a new section and sub-division were announced in May 1943. A new Tilford section of the Farnham division was created as well as a new sub-division formed at Haslemere, in the Godalming Division, comprising the whole of the Haslemere urban district.

A recruiting call went out specifically for women Constables in 1944 and 1946 to increase their ranks in order to carry out the many and varied duties in which women, girls and children were especially involved. Recruits needed to be between 22 and 35 years of age, single or widows, not less than 5 feet 4 inches in height and of good physique. Pay on appointment was 79s. weekly plus boot and lodging allowances.

Recruiting also extended in relation to the Police Auxiliary Messengers Service after their disbandment 1 January 1945. Superintendent Beacher was desirous to retain their voluntary services with the possibility of the formation of a Police Cadet Corps offering their reinstatement and resuming of duties with the Police. The Reigate Borough P.A.M.S. was established early in 1941 and was one of the first groups formed in the Southern Counties with an authorised strength of 24 with 23 members at the time of disbanding under the supervision of Captain C J Sutton, Head Special Constable and later Divisional Leader. Altogether, 57 youths had been recruited into the unit with many of them passing on into various branches of HM Forces. With disbandment they were invited to perform weekend duties on the central switchboard for the time being in civilian clothes, as their uniforms and equipment had to be handed in.

Mr Simpson was one of 118 applicants for the post of Chief Constable of Surrey Joint Police Force. Three candidates were interviewed. The position carried a salary of £1270 rising to £1570, with allowances totalling £500 a year. Mr Simpson's first day was 2 December 1946.

While Chief Constable of Surrey Joint Police Force, he was one of the earliest rescuers at the scene of a fire at a private nursing home near where he lived. Mr Simpson put up more than a dozen elderly and bedridden patients and staff rendered homeless as the nursing home, with the exception of the ground floor, was completely destroyed by fire. In 1947, he issued a road safety campaign in the light of four deaths, 25 injuries and damage to property or vehicles where vehicles were reversed without due care on 169 instances during 1946.

On 1 April 1947, Surrey Joint Police Force reverted to its old designation of Surrey Constabulary and took permanent control of the Guildford Borough Police and Reigate Borough Police. Under the Police Act, 1946, the temporary amalgamation became a permanent merger thereby perpetuating the war-time emergency measure. The only outward sign of the action was the standardisation of uniform, with the peculiarities of the individual Borough Forces, notably in helmet furnishings and buttons, disappearing. The old Borough numbers on the collars were replaced with figures denoting their enumeration in the Surrey Constabulary.

Some revision of Police boundaries was involved as well with the action to make the amalgamation of the three Forces permanent. The parishes of Esher, Cobham, Stoke D'Abernon, Kingswood, Chipstead, Walton-on-Hill and parts of Coulsdon and Epsom were transferred to the Metropolitan Police with Surrey Constabulary gaining Warlingham and part of Chaldon.

The area within the Borough boundaries of Reigate constituted the Reigate Division of the Surrey Constabulary and its Police personnel continued under the charge of Superintendent W H Beacher, the last Chief Constable of Reigate Borough Police.