Sengho had pleaded guilty to the above on 21 September.
At approximately 22:00hrs on Saturday 17 July, two officers attempted to stop and question Sengho, who at the time was riding a bicycle along Kilburn Park Road, Kilburn.
Sengho abandoned his bicycle and ran off towards ChippenhamGardens and the two officers gave chase. During a further attempt to stop him, Sengho produced a black gun from his trousers. He then pointed it at the officer who dived for cover.
Sengho ran off down Chippenham Road, during which one of the officers was able to pursue him. When Sengho stopped running he turned to the officer and pointed the gun directly at the officer. A loud cracking noise was heard but the gun did not discharge.
Additional officers arrived at the scene and Sengho was detained and arrested.
The gun, which Sengho had attempted to discard at the scene, was recovered and found to be an imitation.
On 19 July Sengho was charged with possession of a firearm with intent to cause fear of violence and possessing an imitation firearm and resisting arrest and remanded into custody.
Detective Sergeant Trevor White, of Operation Trident, said; "Incidents such as these are fortunately very rare, but serve as a reminder to everyone of the commitment shown by officers across the MPS.
The two officers showed strength and determination, continuing to chase Sengho even though he had pulled a gun on them once, not giving up until he was caught.
As a result of the overwhelming evidence collated against him, Sengho pleaded guilty and Kilburn will be that bit safer with him behind bars."
Chief Superintendent Matthew Gardner, Borough Commander at Brent, said: "This is an exceptional case of officers stopping a man who pulled out a firearm on them. Some people would quite rightly turn and run. PCs Tsang and Reidy however chose to pursue chase and eventually they detained and arrested this criminal.
This man used a firearm to strike fear into innocent people. The bravery of two fine officers has taken this person off the streets of Brent."