Police were called at around 7.20pm on Monday to reports of the incident at Beaufort Park. The Metropolitan Police said three people at the address were injured and have been taken to hospital by the London Ambulance Service. Their conditions are not thought to be life threatening.

       Some police officers were also treated at the scene for the effects of the substance.

       None of their conditions are also thought to be serious.

       No arrests have been made so far.

       The Met said in a statement: "An investigation is underway following an incident in Colindale where a corrosive substance was thrown.

       "Police were called at approximately 19:20hrs on Monday, 12 July to reports of the incident at an address in NW9.

       "Three people at the address were injured after a corrosive substance was thrown at them.

       "All three have been taken to hospital by London Ambulance Service – at this early stage, their conditions are not thought to be life threatening.

       "Some officers were also treated at the scene for the effects of the substance after attending the address. None of their conditions is thought to be serious.

       "No arrests; enquiries into the circumstances are ongoing.

       "Anyone with information is asked to contact police on 101 or tweet @MetCC and quote CAD 6733/12July.

       "You can also provide information anonymously to the independent charity Crimestoppers on 0800 555 111."