'Patients suffer exposure to public gaze and the often unpleasant comments of the crowd', lamented Sir William Nott-Bower, the Commissioner, in a submission to the police committee in 1904. Sir William had prepared a report hoping to persuade the Committee to set up a police ambulance system 'to meet the requirements of the City of London ... such as has been available for many years in Liverpool, Manchester, and many of the large towns in the provinces, in Paris and Vienna, and in nearly all the great cities of America'.

In 1903 City policemen took some 1,705 people to hospital, half of them strapped to one of the Force's wheeled hand-litters. These same vehicles were used to convey drunks to the cells of the six City police stations then in existence!

In advocating a horse ambulance system, Sir William went to great lengths to point out the problems of the existing options:

'At present there are no means available in the City for removing a person taken suddenly ill, or the victim of an accident, from the streets to a hospital, save on foot, by cab [horse drawn, of course] or cart, or by hand-litter. The latter is, as a mere means of conveyance, fairly effective, but it has the disadvantages of (1) length of time necessarily taken in bringing it to the scene, and in removing the patient, (2) want of prompt first-aid on the spot, (3) lifting and carrying of the patient by unskilled persons, and (4) exposure of the patient to the view, and often the unpleasant comments of the crowd. Thus, even where the hand-litter is available, a simple fracture may often become compound before arrival at the hospital, a patient may sink from exhaustion or haemorrhage whom earlier skilled aid might have saved, and a considerable amount of unnecessary suffering, mental as well as physical, is caused. Where the hand-litter is not available the results to the unfortunate sufferer are even more lamentable.'

The Commissioner, in submitting his report, was not just seeking approval for the introduction of a police ambulance system. He hoped that the police committee would unlock funds to provide horses for a full-time City Police Mounted Branch. He proposed that the horses would normally be used on the ambulances, the prison vans and for mounted escorts to the Lord Mayor. However, 'whenever occasion arose, all horses and men should be employed on mounted police duty, withdrawing them from their everyday work and substituting for them with the ambulances and prison vans, draught horses and drivers, such as can always be hired at short notice and without difficulty'.

The estimated annual cost of Sir William's whole scheme was £2,163, being £1,384 more than the annual City Police expenditure for horsing requirements. The cost of the suggested scheme did, however, include £600 for the rent of two ambulance stations, £200 towards the hire of two senior medical students from St. Bartholomew's Hospital as surgical dressers (to attend calls with the ambulance) £163 towards the cost of 'signalling' (to call out the ambulances from all parts of the City), and £226 for saddlery, vehicles and personnel. A total of £630 was estimated for the annual cost of forage, veterinary bills etc. 'Dr. Nachtlel, who first brought the question of Horse Ambulances to the notice of the Court of Common Council', wrote the Commissioner, had, with his vast experience of ambulance systems from around the world, estimated the cost of a City Ambulance system alone at £2,700 a year. Sir William's submission based on the scheme he had introduced when Chief Constable of Liverpool, had an estimated net annual expenditure of £1,384. For that sum he was proposing both an ambulance service and a mounted police unit.

Given the very detailed arguments set out in the Commissioner's confidential report to the police committee in February, 1904 for an apparently very cost effective proposed 'double' service system, how could it fail to be adopted and financed? It was not adopted. There was strong opposition on the grounds that the proposed scheme would not be a proper area for the Committee to get involved in. However, some members of the Committee were keen to back a more technically advanced service but were outvoted.

The debate rumbled on for the next few years, until on 13 May 1907 the City of London Police Ambulance Service came into being. Instead of horses, the service purchased an electrically driven motor ambulance from the Electromobile Company in Mayfair. The body was to a St. John's Ambulance Association design and of mahogany panelling on an ash frame – no expense seems to have been spared, now the City had approved the idea of the service.

The original ambulance was stationed in the Pathological Block of St. Bartholomew's Hospital. Instead of paying for student doctors to provide the medical care, as originally proposed in the 1904 report, Nott-Bower used his own policemen as ambulance attendants. Since becoming Commissioner in 1902, he had had ensured that every officer of the Force was trained in first aid and some of them had become very skilled indeed.

A second 'electric' ambulance was purchased in 1909. It was stationed in the purpose-built Ambulance Station in New Street, just behind Bishopsgate police station. This ambulance served the eastern half of the City, normally taking casualties to the London or Guy's Hospitals. The western half of the City was covered by the Bart's-based ambulance, except for night-time and Sundays when the New Street vehicle covered the whole City. A third vehicle was purchased in 1915 to provide reserve cover.

The 'electric' ambulances were summoned via calls from any of the 52 white coloured police boxes strategically located about the City, routed through police headquarters in Old Jewry. The 'electric' ambulances and the white call boxes did sterling service until both were replaced in 1927.

The replacement ambulances were of the Crossley petrol driven type. They were only in service for ten years before being handed over to the St. John Ambulance Brigade in 1937.

Three 25 H.P. Vauxhall ambulances with a 'Lomas' body design were bought for the service in 1937. These had the registration numbers DYR 56, DYR 57 and DYR 58. They were all soon pressed into full-time use with the outbreak of the Second World War, during which DYR 57 became one of the victims of the bombing. For much of the war, members of the Women's Auxiliary Police Corps drove the ambulances and provided the first-aid and nursing skills that were much in demand at the time.

The City of London Police Ambulance Service ceased to exist on 5 July 1949 when, under the provisions of the 1946 National Health Act, the two remaining ambulances and the responsibility for the service was transferred to London County Council.

Nevertheless, the City of London Police has maintained its fine tradition of administering first-aid services. In 1996 it became the first police force in Britain to start to carry portable defibrillators in its patrol cars. Officers are trained to use the defibrilators by the Bart's City Life Saver charity, and as a result two heart attack victims' lives have been saved within the City of London.​​​